I believe that mandatory helmets for anyone riding in a car (driver and passengers) would reduce injuries much more than mandatory helmets for bicyclists. There are many more of them and they are going much faster. It would also be more convenient, since the helmets can simply be stored inside the car when the car is parked.

Interesting question! In the last four years I have divorced, quit my job, had a doughter with my new partner, quit the new job back to the first one and is currently on parental leave. That translates to "dramatically better" to me. Many of the comments seem to focus either on money (I make less now) or the upcoming US presidential election (which doesn't really bother me at all).