Yeah, this happens to me from time to time too, Triforce. It's either a bad connection on your part or something on Youtube's part, that has to do with the videos themselves (often times, you'll find a nice video that always loads slowly or one that always loads quickly) and the connection at that very moment. My suggestion is to check your network settings, and if everything is top notch, then check if Youtube is doing any maintenance (they usually plaster this on every page, so it's likely not that). And if it's neither of those, pause the video before it starts, let it load completely, then watch happily. If it still won't load passed a certain point, then drag the cursor a couple seconds down the line, and let it load/play.
I do support the idea of a common, "ask a question, get an answer topic", but whatever.