Tip Culture in Broward/Miami

When you go out to eat at a restaurant anywhere in Broward or Miami and SIT DOWN you need to tip 18%-20% minimum. My grandparents taught me this.

Not $1 or $5. Lol

We went out and watched the table next to us pick at the most expensive dishes, THEN complain to the waiter when it was time to pay hoping to get something free after eating 1/4 of the food.

What is this?

Why are Americans so disrespectful to each other?