Why do you visit questions and not comment/answer them?

I know I've lurked here for a long time before finally actually creating an account yesterday. But perhaps you've clicked on the question because you also want to see the answers given by others. Another possibility is that you have an idea for an answer, but you see the other answers already given, and feel that you have nothing to add to it.

A lot of the time its because I read the details of the question and realize I'm unable to help or the question is stupid or something.

Some people just don't want to take the time to answer them or something else

Well, some of the questions got tweeted by chris, so many people see, but not answer.

Sometimes something interests me, but I don't feel like I know the answer, so I read what people say but don't contribute. Isn't that how it's supposed to work?

I normally answer whatever I can, but there's no use for me to answer questions where I don't know much or anything about the topic. In those cases, I prefer to hold back rather than give out terrible advice.

Nothing to say. Sometimes I think I know the problem and then it ends up being something different.