Growing up playing Soccer in the US, I never saw many divers. It's a risky maneuver because if you just dive on the ground and the ref doesn't give a shit, your team is now playing a man down.
I do hate watching it happen in the professional leagues. But it seems almost over-represented there, you are more likely to witness a real injury than a fake injury in any actual game of soccer.
a few world cups ago, brazil hired an acting coach to teach their players how to sell a dive and get the foul (which is why it's hard for me to cheer for brazil, even though the past couple world cups, they've been extremely good with not taking dives).
i'm with you though... growing up playing soccer, we never dove or anything because we were too busy trying to win. none of my coaches ever encouraged it or anything. one time, one of my teammates did it during a game... the ref never caught it, but the coach did. he left him on the sidelines the next two games because of it.
i doubt that other countries are taught to dive... i think it's a professional thing because money and fame is on the line over games won and championships... if a dive can get someone a foul and help their team win, then they go ahead and do it. it's just bullshit because it's not a legit way to win.