I used to never wear a helmet. Didn't even think twice about it. Then I got married and pregnant and considered how selfish it is to my spouse and child if I were to die or become seriously injured or handicapped because I didn't care to wear a helmet.
It would be pretty awful and unfair to leave my child motherless or have to be fully dependent on my spouse.
This will be the first riding season I'll wear one and also the first I've owned.
I don't see a problem with other people not wearing one tho. It's their head after all.