Internet wizards: what's up with this?

luvche21 thought this was worth mentioning said
2

I'm in Japan right now (p.s. you should totally be jealous), and my normal internet sites are hit and miss for loading super quickly or horribly horribly slowly.

A couple examples: when I purchase a song online, I can download it (7-8 mb) in maybe 20 seconds. Meh loads nice and quick. Youtube is the worst, and barely stream a video. Gmail is hit or miss for being slow or nice and quick. Using an incognito window in Chrome (ie, so that my wife can use my laptop without signing me out of all my things) seems to make everything even slower.

Any ideas on why some things are horribly slow?