Many years ago, I landed at a resort town in the States. My contract had expired there, the aircraft was theirs, so I had nothing to do except wait for another contract. It was a very nice town, full of people doing resort things. I had picked up a young lady friend who stayed with me even when I had some travel stuff to take to the laundry the next day. I put the stuff into the drier, set the timer, and we headed to the nearby bacon n egg joint. Coming back, she pointed out a poor couple off in the corner of the laundromat, sleeping on the floor. We couldn't see faces as they were curled up facing the wall, but their ragged sack of stuff showed they were not just itinerant adventurers but, rather, just very poor. We got my clothes smashed back into my duffle, and started to leave. I checked my wallet, pulled out a twenty, tucked it into their bag carefully and then left with my young lady friend.
The question came up about doing good deeds. Do we ever really have altruism? What did I get from donating that twenty to the poor couple? I insisted that there is no such thing as altruism. She, a college student (studying philosophy I guess!), argued that there was nothing but loss in what I did because I didn't stop for a "thank you" from the couple. I rebutted, "I did get something from it. I got a good feeling, a feeling of love that only I felt."
She, being Christian, countered with, "What about what Jesus did on the cross? He died for us. He got nothing in return."
"Did he go to heaven?"
"He rose from the dead....." etc.
I eventually made my point (or I think I did) with the question, "Would Jesus have died if he knew he was only going to go to hell and never be with his heavenly father?"
The conversation continued on into "each person does EVERYTHING for a selfish reason." Even Mother Theresa. Even Jesus. Even me.