i hate to admit it, but i agree with your parents.
where I live, a small fraction of the people on public transit are obnoxious, play loud music, talk loudly on mobile phones, put their feet on the seats, eat and drink, litter, and create the appearance of being threatening to public safety. law enforcement agents are practically nonexistent.
because of that the entire experience of riding public transit is, rather than being relaxing, a bit tense. rather than being pleasant, it is often unpleasant.
on the plus side, underground trains get me to my destination very quickly.
if public transport were clean and pleasant, if the stations and trains and buses were safe havens rather than magnets for poor behavior and even crime, i'd get rid of my car.