Looking forward to MidLife Crisis

Oh, greeeattttt. (From WSJ)

Numerous studies have found that our happiness level through our lives follows a U-shape, with folks becoming increasingly dissatisfied as they approach their 40s and then bouncing back from there.
...

It isn't clear why we become grumpy in middle age. It could be that we become increasingly disenchanted through our 20s and 30s as we realize our lives won't be everything we hoped. Eventually, however, we adapt, which is why our happiness rises as we grow older.