My girlfriend got upset after I wasn’t as excited to meet her friend, and I’m confused (M21)(F22) AIW

A few days ago, I had been working for about 8 hours, painting, and I was exhausted. My girlfriend picked me up in the city where I was working, which is something we usually do for each other—walk home together after work. When we met up, she seemed tired too, but we just exchanged a quick “hey babe” and a hug and kiss as usual.

As we were walking home, we passed by her gay friend’s workplace. She asked if she could stop by to check if he was there, just to wave and introduce me. I told her I didn’t really want to meet anyone because I was tired and covered in paint, but she said it would be quick, just a wave. So, I agreed.

She was really excited to see him, which I understood because they hadn’t seen each other in a while. When we passed by, he came out, and we ended up having a conversation for about 10-15 minutes. At first, I didn’t mind at all, but afterward, she asked me, “Aren’t you happy you met my friend?” I responded, “I mean, I’m glad I met him, but I’m not exactly happy happy,” trying to explain that I wasn’t as excited as she was because I was tired and not in the best shape, being covered in paint.

Her mood instantly changed after that, and she seemed disappointed. I asked her what was wrong, and she said I should be happy just because she was happy. She then explained that she often pretends to be happy when we’re doing things that I enjoy, like playing video games or reading manga, even though they’re not her interests.

Personally, I wouldn’t mind if she showed disinterest in those things because I understand not everyone enjoys the same stuff. What bothers me is that I feel like pretending to be interested in something creates a sense of fakeness, and I don’t want her to feel like she has to pretend. After we kept talking, it turned into an argument, and she eventually said that I always bring her mood down, which made me upset because I didn’t think I had done anything wrong. I went along with the introduction, despite being tired and not looking my best.

When we got home, I apologized, saying, “Sorry that I wasn’t as jolly as you when meeting your gay friend after a hard day of working and being in dirty clothes.” After I said that, she got really upset, had a breakdown, and started screaming. She ended up leaving to go to her mom’s, and I was left alone after a long day of work.

The main issue is that I feel like I can never fully express myself in situations like this. When I try to explain how I feel, she either walks away or plays the victim, and it makes me wonder if I’m handling things the wrong way. Am I missing something in this situation?

TL;DR: After a long day of work, my girlfriend introduced me to her gay friend. I was tired and not as excited as she was, which upset her. She mentioned she often pretends to be happy during things I enjoy, and we ended up arguing about how we express our feelings. Now I’m unsure if I handled the situation poorly.