Many people believe that good deeds will be rewarded—but life doesn’t always follow that logic. Sometimes kindness is met with gratitude, and other times, it’s met with the exact opposite.

About a decade ago, I worked as a waitress in a restaurant that offered a fixed-price lunch. One day, an elderly man came in, asked about the price, complained, and was ready to walk out. I felt sorry for him, so I covered his meal out of my own pocket.

My manager scolded me, warning that such acts might encourage others to take advantage and that there was no way to undo what I’d done. But later that evening, an unassuming man handed me a generous tip—just when I desperately needed help covering my rent and other bills. That amount was enough to take care of everything.