You can improve the quality of the video you watch on YouTube. Sometimes when you watch the video in YouTube, probably you will have notice that the video is little blurry or text which is being shown in that video is blurry like low quality video. So you can improve it by just adding a little code in the url of that video. So put that code "&fmt=18" in the end of the url of that video and press the enter key and that's it. Now you can see the difference between before and now. The video quality should be more improved than before.