Because if you can't do/find/eat/experience something in Bangkok, it simply can't be done anywhere.
Bangkok is the craziest city I've ever been, crazier than Times Square on crack at midnight on New Year's Eve, amplified times a thousand. I love Bangkok! The city is always on the go, people are incredibly friendly in Thailand, and the temples seem like they are covered in gems. I've never seen so many colors in my life.
When you are in Bangkok, you really feel like a world traveller, and the city really feels like a world capital, like everyone in the world is travelling with you. Just go. It's cheap. You'll find out. :D