Perhaps you were too subtle, or I simply misapprehended why you found it necessary that your hypothetical person who says no to a custom background necessarily appends, "You are playing the game wrong," while discussing the issue with a person who might say no to a custom background.
¯\_(ツ)_/¯
So, not subtle; just passive aggressive. Cool.
I'd also be fine with saying to players to pick an extra 2 skills and 2 tools or languages and just giving them a generic background feature. Maybe even something that provides a feature like the old second wind ability from 4e.
The signature of champions.
I know. I don't care. I'm saying I'd be happy in changing that to the thing I said.Background features are supposed to grant a bit of narrative power; giving them a combat boost doesn't really do that.
Custom backgrounds all day.
Just be sure to tell your players that they can mix and match any existing background skills/tools/features to their liking and you won't wind up with a bunch of Sailors.
My objection is that Features are codified, and presented as interchangeable, when they shouldn't be. If your character backstory is that you're a noble, then it's already true within the game world that you are a noble, and you shouldn't need the "actually a noble" Feature from the Noble Background in order for that to be the case. If your backstory doesn't include that you're actually a noble, then it's not true within the game world that you are a noble, and nothing written on a character sheet should be able to override that.So, to clarify:
Is your objection that someone can freely mix and match background skills and features to create new backgrounds?
Or that someone could mix and match skills and features to create a new background and call it by the name of an existing background?