Now, either we're all just becoming really grumpy as we get older, or it may mean that as you understand laughter better, and you are getting better at doing that, you need more than just hearing people laugh to want to laugh.
See võib olla tingitud sellest, muutume vananedes ülimalt kibestunuks või hoopis sellest, et kuna vanemana mõistetakse naeru paremini ja osatakse ka ise paremat nalja teha, on ka naerma hakkamiseks vaja enamat kui vaid kellegi teise naeru kuulmist.