Youtube now is support for the high quality video playback, compare to the low quality as we always watch previously, it really imporve a lot. But, if you want to watch the video in the high quality, you may need to click on the link just below the video frame to open it in the better quality page, it may not that convenince.
Youtube developer know about this issue, they actually allow you to preconfigure the playback quality base on your preference. What you need is just log into your youtube account and set it.
Login to your youtube -> Click on Account -> Playback Setup -> Choose the video playback quality
But good thing with with the higer price, by enable the high quality video playback option, it will take longer time and more bandwidth to load the video.