what do you think of those who delete their questions after getting the answers?

Well, if you are a good troll, you will delete this question right after you get a few answers.

Sometimes I do believe that people realize how stupid their question is and delete it out of shame. I can't blame them for that.

The ones that I really get steamed about are the ones that I spend a good deal of time either thinking through or researching before providing an answer, and when you go to update, the question is gone. Again, if the question had merit, it really is frustrating to see that time relating either experience or knowledge go down the drain. But, hey, so is life.

Haven't seen that happen too often. More frustrating are about 90% of the questions going to vote instead of the asker deciding the Best Answer.

well some people like fooling around with the internet. if people delete the question because they think it's bad or useless, whatever.

I think that it's not very nice of the asker. If someone had the same question then they wouldn't have had to ask themselves.