I Like to Write About How I Feel

I do get irritated really easily when it comes to some topics but most of the time when i am angry it comes off as very passive aggressive. This lady was commenting on these people speaking another language and had said "They're probably trash talking us, itd be nice if they could speak English" then she looked at me trying to acquiesce those feelings. It was awkward because she was laugh and I just kept a straight face looking at her and told her the price of the stuff she was buying. Its difficult sometimes in customer service because you can't just tell people off. At the same time I don't want anyone to feel the way the people she was talking about may have felt if they heard all of her comments so I always veer towards passive aggressiveness.