People often exempt themselves from all sorts of obligations with the claim of “The Merciful One exempts a man under duress” (Bava Kama 28b) — that is, when a person cannot keep a certain mitzvah because of circumstances beyond his control, he is exempt from keeping it. People consider even the slightest reason “duress” and then feel free from everything that is good. This is either because they like to rest, to deal in business, have a pain, are weak or ill. A man might even claim that his evil inclination attacks him and he is not able to vanquish it. However, everyone knows that this sort of claim of “duress” is useless in the World to Come; the only thing that exempts a person is a true and total case of duress.
The way to differentiate between true, unavoidable duress and what one rationalizes to be duress, is by imagining that you have an opportunity to earn a huge profit. Would the difficulty be enough of a reason for him to forgo the opportunity? If it is, then he knows that it is indeed a situation of duress. But if to make such a profit, he disregards the circumstance and forces himself by saying, “What can you do? There is great profit to be made. One must force oneself…” then what will he answer on the day of judgment when he is confronted with the fact that he neglected all sorts of mitzvos because of such excuses? He will surely be ashamed and embarrassed. He will not have a mouth to respond nor a head to raise. He will surely be punished. About this it is written, If you seek it as if it were silver, if you search for it as if it were hidden treasures — then you will understand the fear of Hashem (Mishlei 2:4-5).