Careless...?
You... are careless?
You worry about everything and anything all the fucking time. You try to avoid (and help others try to avoid) uncomforable situations. You try to make everthing better, and make everyone happy, without any thoughts of how it affects yourself. You feel you are responsible for anyone you hurt, and you live up to that responsibility (or at least you try your damnedest to).
You would call that being careful
So, when some woman runs into you because she wasn't paying attention, and then proceeds to call you a "careless teenager", yeah, you'll be upset.
You're dreading 4th period... An impromptu speech... Egh...