You should be beyond childish things, or so one would think. No matter how old we get, there are always things that are important to us. Things that seem the centre of the universe, at the time.
It's reconned that females rearly progress beyond the mental age of sixteen. Whoa! Before you ladies start pelting me with rotten fruit. - In the same reconning, males rarely progress beyond the mental age of twelve.
So it may not be such a stretch for us all to exhibit some childish behaviour, now and again. It's hoped that age also gives us a little wisdom, to better deal with these little outbursts.