Last night my sister and I went to McDonald's. We hadn't eaten all day and no one wanted to make dinner at home

We got our burger meals and some other stuff and proceeded to wait in the corner we always do.

It was about 6 p.m on a Friday, which I'm not sure about where other people live, it can get pretty packed in fast food joints. The place did have a lot of people but wasn't entirely as full as I've seen before in other locations. There was also 2 long tables in the back completely full of people who had ordered their food to be delivered to them at the table. I'm gonna estimate it was about 10 people at each table

We waited about 12 minutes and my sister spoke up and said "if we get to 20 minutes I'm going to say something" and I was kind of thrown off, she's never done anything like that and was embarrassed by the THOUGHT of her doing it, but didn't actually think she would.

I told her "well, there's lots of people who got their food delivered to the table, plus there's lots of people standing and waiting, we did order a lot, and you have to take into consideration that there might be training employees"

She didn't care and just repeated that she was gonna ask for the manager. I myself was getting a bit upset only because I have social anxiety and hate being in small crowded places for longer than necessary. I would never say anything to a manager though.

We got our food around 17 minutes in. When we got home I told our step mom about how my sister was about to talk to the manager, and my sister got upset again. I brought up "maybe it was an unexpected rush" as this specific McDonald's doesn't usually get that busy often. She decided to practically yell "they should know when the rushes are! They should be more prepared!" I couldn't handle having the conversation with her so I just took my food and went to my bedroom.

Am I the asshole for not wanting to be near one of those "can I speak to the manager" people?