Role Calling

I'm sick of calling a role and then someone insisting that I play something different because they want that role. As I understand it, it's a first come first serve basis and if I respect that, so should other people. I have had to compromise so many times because of this because I don't want to lose the game because someone else is being stubborn. And I'm not a one lane person, either. I can play almost all roles (except jungle cause I'm trying to become better at it before I play PvP as a Jungler). But every single role that I call, someone is saying "No I want ADC/TOP/MID/SUP" Then autolocks because screw being mature about it. It sets a negative tone for me at the very beginning of the game. Anyone else agree?