Honestly, no attachment to my code demotivates me.

It makes me less responsible for outcome and helpless. It makes it much harder to prove I know what I am doing. Since you modify things however you please despite me not agreeing, I am not the one at fault for maintenance issues. It also means that keeping conventions requires constant negotiation and frankly, if I would enjoy people trying to dominate me or me dominate them I would become manager.

And yes, it should not be about that, but it is about that with a lot of guys.