YouTube
I used to go there a lot when I was a kid, let's just say that because I had an account there when I was a little too young, my experience there was hard to bear with to the point where I got mad at people unsubscribing from my channel because some idiot (who will not be named) posted a hate video about me. It used to be a good site with videos that were worth watching until it became a cesspool full of hateful people and stupid stuff. I rarely watch videos there now.
Wikia
One pure example on how bad advertising can get. Like most people I'm rather picky when it comes to ad-supported websites and Wikia takes the cake on a site that goes a little overboard on advertising to the point where there are ads that bypass Adblock (there's a reason why I have it you know). Heck, I remember the excessive advertisements ate enough resources to slow down my Core i3 laptop which is supposed to be suitable for web browsing. So I try to avoid Wikia as much as possible.
Not really much else I can think of ATM, but those were the two that came to mind right off the bat.
Jade Falcon wrote:Vogons.org
I swear, every time I'm on this site I see a post about a cool retro part and I end up spending money I don't have. 😐
Looks like someone has realized what we all go through here. 😵