I bought and/or leased new and newer used cars for a long time. I found it quite limiting to realize that if I wanted to spend my $ on something else, like a move or taking a new job or traveling, that I was stuck: there was no way I could sell the vehicle for what I owed. THAT SUCKS! Plus, there's the simple notion of what would happen if your friend would lose his job and be unable to pay for his new truck anymore?
My wife and I decided that we would NEVER want to be in that negative quity position again. True freedom lies in knowing that you can ALWAYS unload your car for whatever you may have left on a loan, or better yet not have any loan at all.