My biggest problem with ads is they are designed to steal your attention from the content. I've mentioned this numerous times whenever a website starts crying about Adblocking. If you want me to read your content, don't put full motion video ads on the side right next to the content I'm trying to read. Don't make 2/3rds of the page giant clickable area to redirect me to your sponsor. I'm not visiting your site to see the ads, I'm there for the content that you put so much work into. Ads are typically designed to steal your attention and be obtrusive. Slashdot's ads are pretty much safe, even though I even have the option to disable ads here.
I don't recall who it was but one big site posted a editorial on why they think Adblock is bullshit. It was the same day they had full page sponsorship and basically clicking anywhere that had empty space would direct you to that sponsor and they had every kind of obnoxious ad possible on the site at the same time. If everybody was sensible about ads then I wouldn't use an adblock, I do have the option enabled to allow unobtrusive ads so at least I'm not that big of a dirtbag.
Basically the internet is turning into Idiocracy more and more every day. Animated ads all around and some times with in the content you're trying to read. NOW GO AWAY IM BAITIN.