Not tipping at all is seen as rude in the US culture.
Besides, there’s a difference between below average service and absolutely horrible service. For example, there was one time years ago at a restaurant where my family went out to eat. First, our waiter got my mom’s order wrong. Then, when she mentioned it to our waiter, he picked up the incorrect item off the plate with his hands. I’m sure there’s more that I’m forgetting as it was years ago, but I think our entire meal (five people) ended up being comped. We were not happy.
Not tipping at all is seen as rude in the US culture.
Besides, there’s a difference between below average service and absolutely horrible service. For example, there was one time years ago at a restaurant where my family went out to eat. First, our waiter got my mom’s order wrong. Then, when she mentioned it to our waiter, he picked up the incorrect item off the plate with his hands. I’m sure there’s more that I’m forgetting as it was years ago, but I think our entire meal (five people) ended up being comped. We were not happy.