So... what's your most fun / least fun biomes to play?

I thought it would be fun to compare and understand what makes the game "tick" for different players. I LOVE playing Ancient sewers, even if it is kinda predictable. But there's so much loot and secrets, and the enemies are fun. Morass of the Banished OTOH I try to avoid, feels a bit unfair and I don't have "fun" while playing it. What's your thoughts?