almost 24% tip not good enough

this post has gained a little bit of traction in my city. a pizza shop owner held a promo night to attract business. the owner posted this receipt from one of his servers. he wrote “i don’t normally vent… but we have a pizza promo night to attract business. we have severe that work hard and give great service . but his is just disheartening.”

some people are upset that the server was only tipped $1, & that they should’ve gotten tipped more, seeing as the customer already got a discount on the pizzas. others are saying that it’s almost a 24% tip, & the standard is 20% tip for good service, & that the tip is fine. i honestly can see both sides. what do y’all think?