The Ben Ish Chai zt'l asked the following riddle: Ten birds are sitting on a fence, and you shoot one of them. How many are left? The answer is that one is left because the remaining nine will fly away when you shoot one. You are left with one – the one you shot.
He told this as a mashal of people who run after dead things. They live for seventy or eighty years, run after dead things, like money and pleasures, and don't pursue "live" things, such as Torah and mitzvos. They remain with dead matters, and the matters of substance fly away and elude them.
The same applies to Purim. Sometimes, people run after dead things on Purim and become involved in trivial matters. Minor matters occupy their minds. But there are live things to achieve on Purim (such as simchah, deveikus, praise to Hashem, mitzvos, etc.). Pursue what is alive, and don't get tied down with what is dead.
