Responsible adults are quite frankly supposed to possess ALL of the following. Patience is quite important, impatient people are quite more frankly to make a mistake than a patient person.
Adults are supposed to be reliable. If they buy a car, for example, they are expected to make good on that and be reliable enough to make the appropriate payments. The car dealership would rely on them to make good on the deal.
Punctuality is also important. Adults aren't exactly supposed to show up for an important meeting or appointment 45 minutes late, but rather they are expected to be on time or early.
Friendliness is also important. Adults should be friendly to one another, and to everyone, putting aside petty differences and such. Friendliness is key.
All of these are important qualities an adult should possess.
~Hope this helps!