I don't. I would, but I often watch YouTube and I like supporting their content. Surprisingly, they're not that intrusive for me.
Also, sometimes I turn them on for humor. I get the DUMBEST ads.
For example:
One time I got an ad FOR adblock.
Another time I got an ad for a dating site, which claims "Girl will speak first". What if you are a girl, would that mean you are forced to speak first?
And I keep on getting an ad for the new "How to Train Your Dragon" movie or whatever, and then YouTube gave me that survey asking "Would you watch How to Train Your Dragon in a movie theater?" and I responded "Definitely not." Then YouTube decided, "Oh, he's not interested yet, let's make him by shoving it in his face." So that's the only ad I get anymore. I think it's funny.
Seeing advertisements hasn't felt like a problem so far so I've never used AdBlock on my devices. I also feel like sites appreciate it if I don't block their ads; on another forum I've also chosen to see ads on the site just to support it.
Yes I use adblock, I appreciate some sites use AdSense and similar to generate revenue etc but when they put them all over the site in stupid places and what not it slows my browser down, especially when I'm working so I use adblocker I can browse quicker