Would you agree that everything we do, is out of selfishness?

I can’t recall where I’ve read this, or heard it. But supposedly, every single thing we do in life, can be perceived to be on some level, selfish.

Example:
A group of church members go to an under developed country to help build houses and communities for the poor.

It seems selfless right? But one could argue, these individuals are helping themselves feel good, and they’ve accomplished a goal in their life. So, now when they arrive back home to their church, they receive all sorts of praise and thanks for what they did, and it makes them feel good (as they should).

Thoughts? Any truly selfless acts you can think of?