Earlier quoted context omitted.
The tip is expected only when you're at a real restaurant. No tip is required for fast food places. No tip is required up front before you're served. You should tip hair stylists and restaurant staff that brings you food or drink. I generally only tip 15 percent and I never tip at a buffet.
Why should you tip the hair stylists though. Isn't the service exactly what you pay for in the first place (same as taxi/uber)? For food I can kind of understand of since they decouple serving and preparation + ingredients. Note that I am not American and am new to tipping. Just curious
Hair stylists, taxis, sit-down restaurants, they all usually need tips. You don't tip the stylist though if it's the owner as of course they would just set their price.