I think there are degrees of shy as well, and people have different mechanisms for getting over them. For example;
1. First time you're in an Ann Summers / Sex Shop style establishment (normally when your about 15 and buying your first real girlfriend saucy undies for valentines day.)
2. Meeting a lassie in a pub or restaurant for the first time without the interference or support of her friends or yours. This tends to get easier as you get older.
3. Meeting a bunch of strangers who enjoy rooting around in tunnels and old buildings.
etc.