Buying High and Selling Low At Just The Wrong Time

Last night, Washington Nationals reliever Joe Beimel picked-up his 1st save of the season - almost two months after manager Manny Acta named him as the new closer following Joel Hanrahan's 1st demotion from the role.  I had rostered him from that point, and finally saw a return.  Wait, I had cut him the day before!

The same thing may have happened with Cleveland Indians' pitcher Carl Pavano, who had a nightmare first game of the season ( one inning, 9 earned runs) and spent the next two months pitching excellently.  Once the nightmare of the past four years was finally erased, he was picked-up only to allow another 9 earned runs on Wednesday.

Is waiting too longer to buy high or selling low at exactly the wrong time a common occurence in fantasy baseball?  I know the fear of doing this is the biggest impediment to making moves, but how often does it actually happen?  My guess is it occurs once or twice but leaves a lasting impression that affects behavior for long after.

I still think a guy in my AL-only league won't sell low because I snagged Tony Clark from him in 1998.