Why I hate Flash: outside of youtube, 95% of all Flash content is just advertisement - including flashy corporate home pages. Very little actually affords any utility to me.
Flashblock is by far the most valuable Firefox extension that I use.
In that case, you should actually like Flash. Several commenters here say that standard, open technologies like Javascript should be used instead, because they can do everything Flash can do. But if that happened, all the annoying stuff that is currently in Flash would simply be ported to Javascript. And it is much more inconvenient to block Javascript than it is to block Flash.
What we have now is an almost ideal situation: Much of the stupidest stuff on the web is in Flash, little of the important stuff needs Flash, and Flash is easy to block.
True enough. Though if it weren't for Flashblock, it would be a whole different situation. (I'm often surprised to find out how much I'm "missing" when forced to use IE)
Flashblock is by far the most valuable Firefox extension that I use.