Does not matter how fast your connection is, if the sever you are accessing is over-loaded or just plain slow you are going to have issues with the site loading and functioning. Case in point, YouTube. During peak times YouTube servers are very busy and videos don’t buffer as quickly they would during non-peak times. So what happens when you go to watch a video it plays for a few seconds, stops and re-buffers and starts again. Problem is if the video is more than a couple minutes this becomes very annoying very quickly.
After a little trial and error I found that if I stop or pause the video and wait a bit for the video to buffer then it plays fine. Upon doing a little research I came across a GreaseMonkey script that does this for you.
I’d rather just cache the whole clip first then watch it – which is precisely what Youtube Buffer Video for Greasemonkey is designed to do.
Install and activate it, and autoplay is automatically disabled on YouTube pages. Sit back and let them buffer as long as you like, and click play when you’re ready.
Source: Download Squad