I always opt out. I fly ~6 times a year (so twelve trips through security). Different airports are different. SFO is the worst I have dealt with. I get question

I always opt out. I fly ~6 times a year (so twelve trips through security). Different airports are different. SFO is the worst I have dealt with. I get questioned by that security gate about why I am opting out in an agressive manner. My real reason of opting out is to slow down the whole operation more than health concerns. Sometimes the pat downs are actually relaxing (like some sort of strange spa treatment). Sometimes they are rough when going up the leg until they meet resistance...but most of the time they are gentle.