I am asking this question since I don't play HU very often and don't know much about etiquette and stuff.

I was playing a regular session at 6max PLO and due to the nature of my stakes I had to start some games and play HU. I played a couple of tables against a reg, who I respect a lot and we chatter a bit and he proposes playing 4 tables HU, I decline. Both tables fill up, one of them soon disbands and we resume playing HU. I run very good against him (which shouldn't matter) and after I guess 45 mins of play I decide to wrap up the session and sitout (without notice). He says: "Are you joking" and "I shouldn't even explain to you why this is bad mannered". But I really don't...we don't have any form of agreement beforehand and I don't feel like having any obligation to continue + I didn't button him or w/e.

Thoughts on this?