So, this has come up many times before and I see my responses have changed over time. I think I have walked the fence and offer this.......
Most of my friends are cool as can be and are typically the ones who bring fruit for wine, donate sugar, trade, work, or straight out order a kit to brew. I have lately been less inclined to share what I make, not selfish at this point, it's just that I make what I like and other folks might not have the same taste. My wine is usually an absolute hit and is accepted almost everywhere I go, so I understand people slamming glass after glass something that took years to produce.
For your "thirsty" friends, I will admit (as I have done in "younger" posts) I have developed some games I like to play. It depends on the who exactly is bugging me and how bad but I've become pretty prankster on this.
There's the dreaded newbie Bottle Bomb, mark a bottle, over prime with sugar, crack a few with the cool folks, and......... pfeiiiszzzzewzzzz.... damn sorry man that one was a soaker, I'm not totally getting the hang of bottling. Here here's a PBR, sorry man.
The Off Batch- made a mistake? didn't come out right and you thought of dumping it. Hell no, bottle that bad boy, a little dot on the corner of the label. Crack a couple of your choice brews and just straight down em like a champ and say "damn that was good, right?". They'll look at you like you're nuts and probablly never ask again.
But for the most part I really only share with like minded folks. Seems like you are on the high road though and some of the other posts would be better to adhere to. I just love f in with people and it gives me great joy to see the expressions on their faces, uuggkk this stuff will make you go blind, you are the worst brewer in the world, damn man read a book about brewing, just priceless.
Cheers! Keep on brewing.