I really dislike the new loading bar in the YouTube site as videos continue to play while the next page is loaded. I'm on a fast connection so normally youtube loads instantly anyway, but this new method takes 4-10 seconds.
even worse is that there is no cached video while seeking. Even seeking to a "loaded" part of the youtube video results in the reloading the video from that point. Rewinding 10 seconds results in having to reload the video, wtf?