Why are basketball dunks such a big deal?

I don't watch basketball that much, but I do watch sports highlights and they often feature basketball players dunking the ball.  Now some of the dunks I think are pretty impressive.  If they dunk over someone taller than them or if they have to extend far then I think they deserve the reactions they get.  Alley-oops are usually pretty impressive as well.  However some of the dunks they show in the highlight reels or that people cheer loudly about really don't seem that great to me.  If a 6'9" player runs up and slams the ball in the net it really doesn't seem that exciting.

Here's a link to someone asking this same question.  The conclusion seems to be that usually people won't be excited about a really tall guy doing an easy dunk, but regardless, dunking is hard for the average person and it can be exciting to see someone do something that you'll never be able to do.  Especially if it's a shorter player dunking than it's a big deal.  Well I suppose I agree with those statements, I still think that some of the dunks in the highlights aren't that impressive looking.

The funniest thing I read while searching around about this was this article on dunk reactions.  I think I agree that some of the reactions are better than the dunks.