10 year old throwing a tantrum over not getting a new shirt. WTF?!

My 10 year old son’s school has an event today for which the kids were required to wear a white shirt. It didn’t have to be any particular kind of white shirt, just a white shirt. Now, I don’t buy white shirts for myself or my kids, because they have inherited my tendency to be a messy eater. White shirts don’t stay that way for long around us. They do have a couple of white shirts that their school gave them.

He had somehow gotten the idea that we were going to go out and buy him a plain white T shirt for this. We told him we weren’t going to do that, that he could wear the shirt the school gave them, or wear one of his dad’s white T shirts that he wears as undershirts. He went BALLISTIC. He was SO angry that we weren’t going to go out and get him a new white shirt.

I was like, wtf?! When he had calmed down later, I asked him why this was so important to him, and he said he didn’t know.

It’s not like we were going to get anything particularly interesting. We don’t buy new clothes for either of our kids very often at all, so it’s not that he’s spoiled by getting new stuff all the time. I’m trying to figure out what’s going on here, and I’m baffled. Any ideas?