Do you tip before you get the meal?

In the US, it wouldn’t be customary to tip before receiving service.

In my opinion, the 15-20% tip is so expected and routine in the US that the supposed incentive of a tip doesn’t make your service any better. Everyone gets roughly the same service and everyone gives roughly the same tip. It might as well be abolished.

It’s also worth looking up tipping practices and its segregation history in the US. Essentially, it became popularized because it was an easy way to get around laws surrounding the end of slavery and integration. The employer isn’t allowed to discriminate based on race or other factors, but the customer is allowed to.