I was having a discussion earlier about PC race, and I noted that my preference is for players to 'default' to human characters but that my players have a very different view and will basically never choose a human PC. And then I found myself imagining that I'd been asked the question of what happens if these impulses come into conflict.
My answer is actually simple on this one: the player gets their way.
The principle that I work to is that the PC is basically the only thing that the player gets to control. And the PCs are the only thing in the game that the DM does not get to control - the DM gets to choose literally everything else.
And so, my principle is that when it comes to what players do with their character, the DM's position is "hands off!"
(I'll also note that while I may come here, or other places online, to complain about this and other things, I don't do so at the table. When I say this is the players' choice, I really do mean that - there's no passive agressive grumping that they didn't do what I wanted.)
I may well have posted on this topic before. But I couldn't find it. So if it's a repeat... oh well.