Whats a random act of kindness you experienced or witnessed that stuck with you?

While I am unable to provide “bigger” random acts of kindness to large groups of people (it’s one of my dreams to be able to do so) I try to do one random act of kindness, like paying it forward, giving compliments, helping my neighbor out by shoveling snow or cutting grass, etc. per week. What are some things you do, have experience, or witnessed, that has stayed on your mind since?