I don't want to tip the bartender.
Why don't you want to leave the bartender a tip?
I saw someone else tip them already and I don't think they need more.
I could see why you would not want to tip after seeing them get so much money but as long as they're providing good service it's expected that you give them a tip. Those workers make less than minimum wage so tipping when they do well is what you should do.
I'm never giving those greedy bartenders a tip.
I don't think they are greedy, they're just making a living. If you don't have the budget to tip, you shouldn't eat or drink out.