Always check your restaurant bill to see if the gratuity is already included. A lot of them are now sneakily adding 18% to 20% automatically to the bill yet leaving in the custom tip line which can trick you into paying your usual tip on top of the one they’ve already added. So if your food bill is $100, it may arrive with a total of $120, and if you don’t notice and add your usual 20% on top of that, you’ll pay $144 which is a 44% tip!