Too late! Let it be. Best you can do now is, as others have said, a friendly wave, or watch for an opportunity to display consideration or kindness. Now, when someone goes off all crazy toward you, can you be the calm adult? If or when that happens, whether your neighbor is ever to find out, I'm pretty sure that is what he would want for you.
"A man is a success if he gets up in the morning and goes to bed at night and in between does what he wants to do" --Bob Dylan.