Stress is a problem, because with too much of it, you start making bad decisions.
The same is true of a number of situations when you find yourself in a passionate state (stress being just one of these states; tired, hungry, sexually aroused also qualify) Dan Ariely ) author of Predictably Irrational makes some interesting observations about this.
In his book he describes an experiment where people were asked to grade how appealing various sexual scenarios were. They were asked to do this in a “sober” state, and in a passionate state. Passionate state being whilst masturbating, just before ejaculation (you had to ask?). Results demonstrated that they did indeed find some questionable stuff much more appealing in the aroused state than in the “sober” state. The experiments ran deeper than described here of course, but the interesting conclusion is this: Your take on things change when in a passionate state. Furthermore, you do not know your “passionate” self since the “sober” you and the passionate you have never met.
The implications of this are actually rather huge. When under stress, you change, and someone else is in charge. Someone with other values than you. Someone you don’t know. To me that sounds like pretty fertile soil for cultivating f**k ups, don’t you think? So, just keep calm, and carry on.