The Gemara (Chullin 139b) asks: "Where is Haman alluded to in the Chumash?" The Gemara answers that his name is indicated in the pasuk: המן העץ אשר צויתיך לבלתי אכל ממנו אכלת – “Did you eat from the tree that I forbade you?” (Bereishis 3:11).
Rav Elimelech Biderman comments that this pasuk perfectly describes an aspect of Haman's bad nature, because he would constantly mope over the errors of the past. Haman, Amalek, and all those who go in their ways are always asking themselves, why did I do this? Why did I make this error? They are always condemning themselves for past errors, and their hearts are filled with remorse. In contrast, tzaddikim constantly think about the present, and therefore their hearts are filled with joy.
Even when one sins, it isn't wise to constantly harp on the aveiros of the past, because this will draw him down. Although there must be designated times for doing teshuvah, it isn’t healthy nor productive, in our generation, to be continuously focused on the wrongs of the past. One needs to ignore what happened, and move on.
Certainly, regarding worldly issues - matters where one doesn’t have free will - it is wrong to mope over the past, since we believe that everything happened according to Hashem's master plan.
Rebbe Yechezkel of Kuzmir taught, a person walks thousands of steps each day, and one must believe that every step was destined from heaven. If one doesn’t believe this, then in the morning when he says the berachah: המכין מצעדי גבר– “who prepares the steps of man”, it is a berachah levatolah [a berachah said in vain], because he is demonstrating that he doesn’t know that wherever one goes is pre-destined from heaven.
It is therefore improper to mope and beat oneself for making a wrong choice in a business venture, or any other decision, because we believe that these are also from Hashem. Our focus, instead, should be on the present.
The Gemara in Shabbos (63b) states: עד כאן דברי יצה”ר מכאן ואילך דברי יצר טוב – “Up until here are the words of the yetzer horah. From here on are the words of the yetzer hatov.” The Binyan Dovid explains that when a person thinks all about what happened up until now, it is the yetzer horah. When a person's focus is on the present and future, this is the yetzer hatov.
After the Holocaust (WWII), someone asked the Satmar Rav to state his impressions and thoughts on the devastating holocaust. He replied, “A Yid doesn’t think about what was.”
HaRav Moshe Wolfson, Mashgiach of Yeshiva Torah Vodaas, related the following story: Once after kiddush levonah, the Oleka Rebbe, a talmid of the Ba’al Shem Tov, turned around to his talmidim, and said: “I want to tell you, my dear talmidim, what I just saw in Shomayim. A neshomah must come down to this world and do all the 613 mitzvos, to do what it is supposed to do, and fulfill its mission. If not, it must come down again. That is the worst thing that can happen to a neshomah. A neshomah would rather go to gehinom than come down to Olam Hazeh again – because it is a big risk. Most people fail! (Rav Wolfson noted that coming down into this world again is like running across Ocean Parkway against a red light.) But the neshamos keep coming down again, and again.
“So, the neshamos protested. They all came to Duma, the malach in charge of the neshamos in Shomayim, and they said, ‘It’s no use. What does the Creator want from us? He keeps sending us down. We spend our seventy, eighty, or ninety years in Olam Hazeh, and we go to the grave, and we go up to the Beis Din Shel Maaleh, then they send us down again. Up again, down again. Mission not accomplished. It’s no use, there’s no end to it; there’s no purpose in it! What do they want from us?!’
“The malach Duma said to them. ‘I cannot answer you. I will send you to my superior.’ They went to the malach who was higher, and they again voiced their protest. He also told them, ‘I will send you up above, to a still higher malach’. Higher and higher they went, until they reached the malach who is in charge of all the malachim. He told them, ‘I will send you to the Ribbono Shel Olam Himself. I do not know what to answer you.’
“So, they came to the Ribbono Shel Olam and they said, ‘Father in Heaven. What is the purpose of it all? We keep coming down again. We are not getting anywhere.’
“So, the Creator told them, ‘I will tell you what. You go down again in this world, and if you’re going to do aveiros... we’ll be lenient (as long as it wasn’t done rebelliously). One thing I want you to do though: have emunah, believe. Believe that everything that happens is from the Ribbono Shel Olam. However, there is one condition: the emunah should be of a higher degree. You should never use the word “would.” Meaning, never say, “If it would have, it should have, it could have...”’”.
When a person says, I should have done things differently, it implies that he doesn’t believe in hashgachah pratis. He thinks that his destiny is in his own hands. If one can avoid saying, “I should have,” he will succeed in his mission in this world.
For example, Mr. Levi comes home from Shacharis, and he has a business appointment. This appointment means that he can make a lot of money. He comes home and breakfast isn’t ready. His wife hurries and makes breakfast, which he gobbles up and hurries to the train, which he misses. With this, he missed his appointment, and because of that, the business deal fell through. So, he comes home and tells his wife, “If you would have made me breakfast on time, I would have made a lot of money. But because of breakfast I missed the appointment.” That means he has an imperfect emunah. Why? Because he should know that being successful in this business venture depends solely upon hashgacha pratis from Shomayim.
Every tiny incident that happens in this world depends upon hashgacha pratis from Shomayim. There is individual supervision to such a degree that it is mindboggling. No computer that has ever been invented can understand the hashgacha of the Ribbono Shel Olam. The Ba’al Shem Tov said that if a blade of straw falls from the wagon, it is min hashomayim [Heavenly determined] exactly where it should fall, and exactly which end of the straw should point this way, and which end should point that way. Everything is hashgacha pratis. There is nothing that isn’t exactly the way the Ribbono Shel Olam dictated that it should be. When I go into the grocery store and buy a loaf of bread, it was determined in Shomayim which kernels of wheat should go into which loaf of bread, and which person should eat it. Everything is hashgacha pratis from Shomayim.
So, if someone says, “I should have done this, I could have done this, if only I would have done this...” that is a blemish in emunah. It is not perfect emunah.
If you are supposed to be successful from a certain business endeavor, the Ribbono Shel Olam will control everything so that you should be successful. And if not, you’re going to miss the train. One should be in the habit of saying, “Everything the Merciful One does is for the good” (Berachos 60b), and, “gam zu letova — this too is for the good” (Ta’anis 21a). There is nobody in the world who cares for me and loves me, not my parents, not my grandparents, not my rebbe, as much as my Father in Heaven. He provided for me since I was born. He put together a mother and a father for me. And I had to be born specifically through this mother and father, in specifically a certain month, in a certain week, in a certain day, in a certain hour, in a certain moment so that it all fits into my mazal in Shomayim. The Ribbono Shel Olam has a special mission, a special job, a special calling for each individual.
Everything that happens in a person’s life, everything that happens in a person’s day, everything that happens in a person’s moment is all with hashgacha pratis from Shomayim. So, someone who really believes won’t say, “would have..., should have..., could have...” He’s happy with what the Ribbono Shel Olam has sent him, and he thanks Him for taking care of him. In a certain way, he turns to the Ribbono Shel Olam and says, “I thank you, Ribbono Shel Olam for being my babysitter.” This is what Dovid HaMelech said (Tehillim 131:2): “As a suckling child near his mother; my soul within me is as a suckling child.” The Creator takes care of us like a mother takes care of her baby, and more so. Everything is with hashgacha pratis.
“So,” said the Oleka Rebbe, “the Ribbono Shel Olam told those neshamos, go back down to the world and if you make some mistakes, I will overlook it (as long as they were not done rebelliously). But have emunah. Know that everything is with a very detailed heavenly supervision, and the words “would have..., should have..., could have...” should not be in your dictionary.” (R’ Eliezer Parkoff, Weekly Chizuk)