וַיְשַׁלַּח אֶת הָעֹרֵב וַיֵּצֵא יָצוֹא וָשׁוֹב (ח:ז)
The Suspicious Raven and the Trusting Yonah
Rashi says that when the Orev (raven) was sent out of the Teiva, he suspected Noach of wanting to get involved with his mate. This is because the Orev (raven) himself engages in stealing and illegal activities (they trick smaller birds, and thereby steal their meals, i.e., worms). This is the Klal of: כָּל הַפּוֹסֵל בְּמוּמוֹ פּוֹסֵל, when a person criticizes someone else, he usually has the same problem. (Chazal). Notice how the Yonah (dove), who is known for his loyalty to his mate, never suspects Noach.
A person whose nature is to be a skeptic, but he works on Temimus (like Noach Ish Tzadik Tamim) and he forces himself to see only good, is a real Tzadik. Dovid HaMelech was known for his Ayin Tova, although he was a shrewd Admoni by nature. (Of course, sometimes you must be: כַּבְּדֵהוּ וְחַשְׁדֵהוּ, respectful but cautious).
Working on Temimus is very hard, and when someone praises you, try to insist that: שְׁכִינָה מְדַבֶּרֶת מִתּוֹךְ גְּרוֹנוֹ, it is the Shechina that is speaking through this person's throat, and Hashem wants to give you a boost (and stop putting yourself down!)