YouTube is the best video website on the internet. Like most video websites, it survives on ads. Now there is nothing wrong with that. UltraLinx survives on ads too. However I don't let the ads get in the way of the content on UltraLinx, ads do get in the way of content on YouTube though.
Luckily on YouTube you do get to skip most ads. Unfortunately there is an ad or two which you're forced to watch. Also when you don't have a fast connection and you get buffering ads, it's bloody annoying.
ScrewAds a neat little extension for Chrome that skips and block ads on YouTube videos. There may be the odd video where an ad appears but on most videos you shouldn't see an ad at all.