Man, this is such a simple concept. I can't wrap my head around the fact that so many are just not getting it.

1. A bartender's job is to tend bar (yeah; radical definition, I know). Tending bar involves fulfilling reasonable customer requests in the area of drink service.
2. Yes, there are usually two (or more) sides to every story. Another radical thought: I tend to give credence to the stories of long-time FT members, unless they have an extensive history of whining.
3. The OP is fluent in English but clearly not a native English speaker. Therefore, one has to make allowances for the use of certain words that may seem exaggerated. For example, the French say "Je suis désolé" as a simple "I am sorry." The literal English translation "I am desolated" would seem completely OTT. We can apply the same understanding to the OP's use of the word "humiliated".
4. Whether or not the OP was indicating that he was going to leave a tip has ZERO relevance. Tippers and non-tippers should receive the same service. Before the self-service machines, I always tipped a dollar or two for a Coke with ice. I don't remember it ever being refused because of the triviality of the task.
5. When I'm paying $500/year for a membership at a "club", I'm entitled to get "service with a smile" to all service requests.

That is all.