I was also worried when i first started about the potential effects of stress of always dealing with real time P&L, but you have to develop an understanding that you cannot control the lines on the screen and how they move. Its a job with a lot of uncertainity, and you have to embrace that. Now this perspective is only possible if you are prepared every day and do your homework, because only then can you think, whatever happens, I am positioned the right way according to the information I had this morning. If something comes out like a company unexpectedly profit warns and drops 10%, you need to think, did I have the info before the event to expect that? If yes, then you need to learn from that mistake, if no, you need to write it off as a cost of dealing with uncertainty.