American kids may not have that 'handicap' and they do usually top the tables, by a fair margin, in the confidence metrics, a confidence which isn't always matched in ability. Being reserved is not always a bad thing, but it has to be a balancing act.
We thrive on being the underdogs, we pull out our best performances when people simply write us off. Even in recent history, where we don't pull out the win, we still give much bigger teams a run for their money (going down 3-2 to England and 4-3 (agg) to Spain, both just last year). Heck, we must be doing something right, earlier this week saw a youth player from the domestic team I support being bought for several million by Sporting Lisbon (Ryan Gauld, a name to watch in the future). I've watched the sporting greats of my country through the highs and the lows, and there are plenty of those. You may call it a handicap, but sometimes having the grit instead of the faith or knowing you're the wee guy going up against a giant - is all the motivation you need.