Saying something that is more a positive aspect rather than a negative one is very overused and will be seen as avoiding the question nowadays, employers look for people who will admit to their weakness and their incapabilities, they'd rather hire someone who's self aware and tells so than someone who says something that'd make it look like you don't really have a weakness. Don't make it too terrible of a weakness though, say something like: I can be forgetful sometimes.
