How about talking loud on a train?
Why would you talk loudly on a train?
I just feel like it for a change.
You shouldn't talk loudly on public transports as it is quite rude and disturbing to others. It is thoughtless and disturbs other people who just want a quiet ride to their destinations.
But I am a teenager.
You don't get a free pass to talk loudly in train just because you're a teenager.  You should get a hobby or something to have fun instead of finding amusement in disturbing other people.