Kind of challenging

I feel like I've had a bad day, not because stuff went wrong, but because my mistakes built up and I got down on myself.  I know a lot of people who are much harder on themselves than they are on others.  I've heard that if we can learn to be kind to ourselves everybody around us will benefit.  So, here's a challenge: You've heard of that concept "Pay it forward".  What if we pay it... inward?  Which one's harder?