Why do some women get pissed when they cause their guys jacking off?

My buddy just called and asked if he could stay here tonight because his wife is super pissed because she walked in on him pleasuring himself. I get it if he wasn't pleasing her but that is not the case with them.
My wife is out of town tonight and I will no doubt end up climaxing myself before the night is over, and I am sure my wife could care less as long as I am ready for her when she gets back. Any thoughts for anyone out there.