Recent studies have shown that a psycho comes in all shapes and sizes and they are far more than we think. So beware of your colleagues!. Here is the article on "Here's How to spot a psycho" which appeared in New Scientist.
Here in one more article which i came across yesterday evening and caption goes like this "Watch Out! Your Smart Boss Could Be A Psycho".
I think by now you would be analyzing about your colleagues/boss whether he/she is a psycho after reading these two articles. Anyway which ways be happy if you have good colleague/boss.
But always be prepared to face them anywhere anytime.