I say "Okay" or "thanks." Sometimes I am shocked I get one because I wasn't expecting it. The other night my bf and I got in a fight about something because he had done something that morning that upset me and I was screaming at him and getting very very angry inside and felt like beating him so I left the living room and went in our room and I still felt all the anger inside me so I broke into tears. I wasn't expecting my bf to come in the room but he did and said "I'm sorry." That seemed to take away all the anger and I was feeling better all of a sudden. I didn't really saying anything about the apology at first Then I said I wasn't expecting him to come in and I wasn't expecting an apology either.