43 Web Design Mistakes You Should Avoid A lot of these are self-evident, or should be. I've never seen such a comprehensive list though. My personal favorites are:

6. Do not resize the user's browser windows 15. Do not break the "Back" button:

34. Do not use animated GIFs:

There are some good comments there too. I have to agree with the comment about spelling and grammar. I've seen that cause some serious confusion.

h/t Blog Marketing Singapore