Parting.

"Good night, good night! parting is such sweet sorrow,That I shall say good night till it be morrow" 

 Shakespeare  knew. Parting is always bittersweet. It is not only when you're leaving for good,

 it is as well when you're leaving for short period of time.

I think this is due to the fact that leaving is always separate ourselves from the comfort of the known, usual routine for something new, exciting and unexpected. And if when you're 20 the question if the unexpected and new is more desirable than the routine is utterly rhetorical, when you hit 30 this starts to be a question that wants an answer.

 

So, so long to the new at all cost. We start calculating if change is worth it. We start calculating the consequences of our decisions, and to consider the probabilities of success.

Basically, getting older means becoming a mathematician!