why are bar maids are called wenches?

So, this past saturday After heading to the Grand opening of Hamiltonian Gallery We decide to retire to the black cat. This bar is the old staple for kids who either want to be hip, and don't know where the hip place to be is, or maybe are getting a little too old for the bar, but still wish they were cool. I belong to the latter group. I think. The bar is split into two levels, one for national touring acts Upstairs, And a bar with a small room in the back for local shows. The shows there are generally good shows, both upstairs and down. In fact, this is the place i probably go to see shows in DC most often. I know that DC is expensive, I know that times are tough, I know that old is the new new, and crappy is the sheik good, but this bar is guilty of one of my all time pet peeves. This is the fact that the bar maintains a low brow motif, Torn couches, sticky tables, bare bulbs, crooked pool tables, misfits on the jukebox (actual jukebox also, which is cool. not the digital download in your pants type), All the general characteristics of a Dive bar, with two exceptions, Price and attitude. The cheapest beer is a 350 PBR, Again not bad for DC, but not congruent with the atmosphere either.
Either way, once you get passed the distinct smell of aging hipsters and lavishly priced PBR draft in the place, the shows are generally good, and there relatively fewer conventional idiots there than in around the Area. plus it is Right down the street from the velvet lounge, where you can party to the tune of natty boh for pennies on the dollar. ( i do not know what that means.)

So here is my dilemma. I Consistently tip at the bar, not a lot, but consistently. I don't order complicated drinks. beer, whiskey, highball, tequila chances are pretty good that as a bartender serving me, you wont need your shaker. I wait patiently, I dont flag the barman or wave a 20 at him/her. all in all I feel like i am a pretty good bar customer. Or i did, until this weekend.
Here is the order

4 tequila, (It was a friends Birthday) one PBR draft. Total 31 dollars. In my pocket, 32 dollars.
The bartender fixes the drinks, and i gave her all of my money. I didn't ask for change, and she put the single on the bar, so i slid it to her end, and told her it was a tip, which she replied that it was not, and slid it back to me.

Fuck you.

First off, yes, in fact it is a tip.
Second of all you filled 5 glasses with liquid, and 4 of them were tiny this took you 30 seconds.
Third, Don t play blue collar bitch/white collar snob with me lady, I went to art school, I fucking know the rules to that game.
What the fuck is this, you probably make more than i do as a fucking bartender anyway, just because you need a fucking mortgage to pay for your shitty sleeve tattoos is fuck it, lets not make this personal.
Third if you want people to come in and order champagne and tip you with a fist full of jewels, don t work in a faux Dive bar which attracts artists, musicians and vagrants such as yourself. Get on some Philip Pirrip/Oliver Twist shit and move to georgetown.

I might be wrong here, but I feel so right.
Comments and questions.