You can't explain that

It's an anime about pirates and fruit that turns you into rubber. It does not surprise me in the least that the swords get the couch and the people get the floor.
Besides, maybe the couch is really uncomfortable.

I love One Piece! I'm on episode 67 so I'm far behind. Yeah...

its obvious, zoro and sanji got into a fight whos got to sleep on the couch, so in the end none of them do

No it's obvious that Zoro's swords are more important to him than his own comfort.

Excuse you sometimes the floor is more comfortable than the couch. Or they are really lazy. I mean, this one time I just slept on my floor instead of my bed because I was too lazy to clear off my bed.
(Sorry if I didn't accurately describe the characters or that couch. I don't watch a lot of anime.)

You hafta love Chopper (the reindeer with the red/pink hat on the left) and Luffy (the person on the top hammock)