Under!!!! Are you over people crazy or somethin'???
Just kidding! I'm ocd and hate it when I see someone put theirs over. Though the piles of laundry, toys, recipes laying around my house don't seem to bother me at all.
When my husband and I first got married we had a bathroom etiquette discussion. Two of the main 'rules' discussed were the toilet paper must be OVER and both the toilet seat and the lid must be down.