What plots don't work?

I've been asked to write an article for a mystery magazine and I plan to write about irritating plots. 

Readers, do you have any favorites?  For example, I really dislike a mystery where at the end you discover that critical information has been withheld so that there was no way the reader could have deduced who the culprit was. I like to have a fair chance to figure it out.

What about you?  What don't you like in the mysteries you read? Please comment in the comments.