What to see in Bangkok you'll find everywhere. Temples, markets, the Grand Palace: the same ten photos on a thousand sites written by people who spent a week here.
I actually live in Bangkok. And what's missing for the people who land here isn't the list of monuments — it's understanding how the city works. Bangkok isn't a city you visit: it's a city you read. It has neighbourhoods that change face every block, a nightlife that's really five different nights, a way of getting around that costs you time and money if you don't know it.
Below I've split the city up the way you'll actually use it. Not the way the guidebooks package it.