Sure, I do. Same reasons as Simone’s and chyna’s. Also sometimes a question has already been adequately answered and I have nothing of interest to add, but I still admire the question. And sometimes it simply sparked a great discussion and I want to say thanks.
For me, giving a GA or a GQ is like applause, and I award it anywhere I think it’s deserved.
Yes, some questions are so good, I’m not good enough to answer them. :-) Sometimes questions are good enough that I think they deserve more thought and attention than I can give them at the time. Or sometimes I’m too lazy to answer them, or sometimes I just don’t feel like answering them. That doesn’t mean it wasn’t a good question in the first place.
Sometimes if I feel it was a good question and someone already gave a response I would have. Another time I do this is when it’s a question I’ve always thought about myself but I have no way of answering it.
Often if it is a subject that interests me but I don’t have an answer. Then I hit the “follow this question” button so I can see how it evolves. Sometimes I will answer later after being inspired by those who go first.