Should I Care?

Joshua wanted to meet some friends at Funtyme. So I drove him there.
And when he was ready to be picked up, he texted me. So I went to get him.
As we were driving home, one of his friends called and they made plans to go fishing. But upon arriving home Joshua discovered that Matthew was using Joshua's bike, so he asked me if I would drive him over to the fishing pond.
He said he'd walk home.
I was feeling kind, so I drove him over there, too.
Before I dropped Joshua off we discussed when he was to be home for dinner, and he assured me he would allow plenty of time for walking - so he wouldn't be late. I probably confirmed his plans once or twice (Being late has been an issue for him...) and then I said goodbye.

Fast-forward to 5:40 that evening as Joshua walked in the door. (He was supposed to be home at 5:30.) His friend (M) was with him and they were trying to get a hold of M's parents to make plans for Joshua to spend the night at M's house.

Oh, silly boy!

Brian and I had already discussed the consequences for Joshua being late and agreed that he would be grounded.(The usual consequence for late-ness.) That meant no sleep-overs.
Even though being grounded is what happens when Joshua misses a curfew, he acted surprised (read that: He acted like I was out of line, the consequence was outrageous, and his world was just about to crash in.) and asked why he couldn't spend the night with M. As calmly as I could, I explained again that he was late coming home and the consequence for his action was being grounded.
He huffed around, went outside with M, and came back about five minutes later. Once more, Joshua asked if he could pleeeeease spend the night at M's.
Once again, I said, "No."
And once again, Joshua asked why.
I started to explain one more time, but was interrupted by my dear son as he protested that we are too strict. He said he was only a few minutes late, it wasn't a big deal, and he shouldn't be kept from this sleep-over. Joshua reiterated that we are too strict and then he hit me with the whammy. He said, "Even M thinks so!"

It took every ounce of self control within me to not come back with a very sarcastic, "Should I care???"
Because I don't.

Instead I think I said something like, "Why don't you start adhering to our rules and expectations, and see if you like the way we respond."

Honestly, it is not my life goal to make my son miserable. I want to teach him responsibility, and respect for authority. Want to prepare him to be a successful adult.
And if that means his friends think I'm too strict, so be it.
Because I really don't care.
*wink*