How do you discipline a friend?
Even when you feel they deserve it, it’s not so easy. Too harsh and you lose a friend. Too soft and they’ll do it again.
I generally advise against giving advice to someone who hasn’t asked for it, but sometimes you know someone well enough. To me friendship means you’re responsible to help a friend.
Below is an example of balancing things effectively. Not that I have special skills in this area, but I hope it helps if you need to balance things sometime.
Context: Recently a friend was late to meet for lunch. He’s always late. So much that the night before I confirmed, something I never do with friends, but I don’t like holding appointments for people who waste my time. In the past five years or so, I doubt he’s shown up on time ten percent of the times we met. On the other hand, he’s coming in from New Jersey, while I only have to wait for him in the city. But then again, our different costs of living adjust for that.
Context texts (edited):

He texted: Looking a little late.

I texted: Okay, I have a 2pm appointment, so hopefully not too late. Looking forward to seeing you. Lots to talk about.

Him: ETA is 1:20pm. Want to reschedule?

Him: [Long explanation, health reasons]

Okay, you have to respect health issues. But he always has an excuse. I think the following text covered the important points—compassion, empathy, and understanding as well as accountability.

Me: I sympathize with health issues but I feel it my responsibility to give some tough love. You’re well beyond boy who cried wolf territory on lateness and canceling.

Me: Let’s reschedule. But let’s also talk today. I have a potential client for you.

His response suggests I hit the right tone.

Him: What time should I call?

Him: Tough love much appreciated 🙂