First time poster here.

This happened this past summer. 

We live in a HCOL area. Lots of wealthy/entitled people. We are not poor, but (very) far from wealthy. 

The wife and I take our kids to the local public park. Now, this park is awesome and FREE. It has a huge splash park, three playgrounds, tennis courts, paved nature trails, etc.

The final cool feature it has, is a full sized carousel. This is the only thing that costs anything, besides stuff at the concession stand. It’s $5 USD per child, per ride. This is where the conflict occurs. 

After a fun morning of splash pad, my wife and I decide to get our kiddos some ice cream and then head to the carousel because you have to buy tickets at the concession stand. The carousel only runs every 15 minutes and by the time we get to the carousel people/kids are piling in. Now, my son can be picky and normally I don’t play along with his pickiness unless he’s willing to be a big kid about it. So, when we see the only seat left is a non-moving horse, intended for very small children, I ask if he would like to wait 15 minutes for the next one to get a better seat. He says yes and waits, just being a good kid, eating his ice cream and choosing the type of seat he wants. 

He settles on an eagle. It’s huge and colorful and he's really excited for it. 

Cue the Other Dad (OD). We make small talk ask our boys, who were about the same age, which animal they are going to pick. My son says the eagle, the other little boy says a lion. Cool. 

At some point in our 15 minutes we talk about how our local movie theater is great because you can pick your seat ahead of time and not be at the will of the “Social Contract” of waiting in line for your turn to pick a seat. From this I get the feeling that we’re both on board with the seat choices and the way our next shared experience should go. I was wrong. 

As soon as we get let into the carousel OD flat out runs right to the eagle and plops his son right on to it. 

I gotta be honest, I was flabbergasted. Normally, I would have just been like “oh well, dude’s a jerk” and helped my son pick another seat. I didn’t this time. I just had had a conversation with this guy. WTH?!

I looked right at the guy and said “ Really?! We just talked about this” He shrugged, as if to say “tough cookies.” 

Nope. Not good enough. 

Now, because of the nature of this ride the seats filled up quickly around us. I looked at him AGAIN and said “Really?” It was uncomfortable, to say the least. 

After a few VERY tense moments, he picked his kid up and moved him to another seat. And his kid started bawling his eyes out. It was bad. I felt bad. I still kind of do. 

I picked my son up and put him on the eagle and he thoroughly enjoyed his ride. We walked home with our ice cream cones. 

So, AITA?

TLDR;
I made a kid cry because I made his dad give my son a seat on a carousel after we had all discussed which seats we were picking. 
I 