I went shopping with my girlfriend. She took a fancy to a trousers skirt, but the waiter had a bad attitude. I won't let her buy it. Let her look elsewhere! But she was angry. Am I wrong?

You are not wrong, but in the process of falling in love, girls will inevitably be spoiled, and you need to give her more. If you don't let her buy it, she may think that you are reluctant to spend money or that you don't agree with her vision, so she will lose her temper. As long as you discuss it with her, I believe she will understand you ~