I really dislike how the game deals with your cars. (Both your default and the ones you buy.)

This is completely me whining like a baby, so feel free to move on if you don't want to listen to me complain. I love the game, I have been playing GTA since three came out. I don't like that if you start a mission with a car you've bought, it replaces it with your default car. What brought this crying fit on for me, I just bought a motorcycle with Franklin, brought it to his new house and parked it in the driveway next to the default car. I move one of the cars in the garage out and park it right across the street. I turn around to put the motorcycle in the garage and it is gone. I know, I just have to go to the impound to get it back. But why the hell did it do that in the first place? Not the first time it's happened. Hope they do better in GTA6. Im done being a little bitch now.