Absolutely
1. legal drugs (pot, mushrooms)
2. cheap beer
3. easy sex (the dutch are, as a group, tall, blond, blue-eyed, fun loving and very handsome/beautiful)
However, A'dam is a city of 750,000 people and every one does not drink and drug. It is what you make of it. I know some americans that came here and have sunk into an unhealthy, desperate dependant life style.