When you’re being nice, you are being polite with the intention of making someone feel good. You may be withholding your honesty because you don’t want to hurt someone’s feelings.

When you’re being kind, you are being honest with the intention of helping someone improve. You will tell someone that there is food in their teeth, even if it makes them feel embarrassed. 

There’s a common sense that comes with being kind. If you have something difficult you need to bring up with a friend of yours, you might pull them aside, figure out a way to gently probe the topic, and ask permission to discuss. It’s still risky, but it’s the kind thing to do. People who only offer tough love usually get confused about why they’re so misunderstood, and eventually run out of people to offer it to.

You need to extend that cordiality to yourself as well. Being overly hard on yourself is the opposite of being kind or nice. It’s hurtful and it’s mean, and it isn’t constructive or sustainable. Sure—beating yourself up or threatening yourself with fear may help you get something done—but at the cost of eroding your social confidence. It’s hard for you to be self-assured when you’re hurtful with yourself.

By contrast, being nice and kind to yourself means you’re comfortable and honest with yourself. Other people around you will feel comfortable around you too. You can only give what you have.

If you wouldn’t say it to your best friend, don’t say it to yourself.