If you are watching a lot of youtube, ads that happen on some of the videos are very intrusive and annoying. You dont want to sit there for a long time watching more ads then videos.
There is a plugin I use which blocks these ads so all you see is the videos. It is also useful for other websites as you will not see ads anymore wherever you go. The software is called AdBlock. It is available for all browsers. I use chrome but it does not matter what you use. I will add the links to these plugins below so you can download them.
Mozilla Firefox https://addons.mozilla.org/en-US/firefox/addon/adblock-plus/
Google Chrome https://chrome.google.com/webstore/detail/gighmmpiobklfepjocnamgkkbiglidom
Your internet experience should be a lot better now!