Is it bad etiquette to bring my own?!?

I went to a restaurant yesterday for lunch. I wouldn't say it was upscale, more like business casual. I ordered a salad and when she brought it to the table I asked for some ranch dressing. She said they didn't have ranch dressing. I had never heard of a place not having ranch lol. Would it be really bad etiquette to bring a packet or 2 of ranch with me the next time I go to eat here? Thanks for answering :^)