I, too, am a nonbeliever. I actually like what Jesus reputedly said: love one another, love your enemies, feed the hungry, heal the sick, care for the poor, be kind to the foreigner and stranger (Good Samaritan).
Sadly, the loudest, most visible and influential "Christians" reject all of those teachings. They are fearful angry and cruel people.
That makes me sad.
I think it's better if people are kind to each other because they recognize we share a common humanity. I'm less impressed if people behave kindly because they want to go to heaven or they fear hell or they are obedient to God. That seems to me to be a hollow morality.
That said, I'm pleased when people are kind whatever their motivations!
Peace.