While it may be true that there are some outstanding ISP issues that lead to slow internet, I think the more pressing issue is the behaviour of the new(ish) youtube player acting erratic. For instance, you cannot fully load a video anymore, it will only load a portion as you continue watching. If you wish to rewind the video, for some reason youtube will want you to rebuffer the entire from where you have rewinded to…
Moreover, the little that is prebuffered seems to behave oddly, you skip forward well within the indicated area that have been buffered, yet the player seems to reset and start re-downloading that part -> unueably slow.