Dear Prudence, 
I live with my best friend (who is a 32-year-old adult). We are both solidly comfortable in terms of funds (and honestly, though my salary is slightly higher, I have pretty substantive loans/debts that she doesn’t have to worry about). Two years ago, my mom gave me a wine of the month club gift for a month, where you get to mix and match a case of wine for a pretty steep discount. Since then, I buy a case of wine a month because it’s actually pretty economical. I understand that this is a bit of booze, but it’s actually a very useful tool for me in keeping my alcohol intake to a certain limit and it’s cheaper.
Since I started doing this, my roommate has decided it’s OK to drink my wine, something she did not do when I was just buying one or two bottles at the store at a time. She has never offered to pay me for this because she “only drinks one or two glasses per bottle” so it wouldn’t be fair. I disagree. I have been fairly annoyed by her unwillingness to chip in, and have brought it up a few times, but I do drink more than she does and at a certain point, I can’t be bothered to fight the same fight about her paying even 10-15 percent of something I buy for myself that she treats as an apartment utility. We have been friends for too long to fight about her stealing my booze (or my food, which she also often does) despite how much I hate people stealing my stuff.
However, I recently bought a few very expensive bottles of wine (like $90-100 bottles) to give as gifts to family members for whom a fancy bottle of wine is the perfect gift. I told her they were presents and stored them slightly separated from the other wine I bought for the month. I went out of town for a week, and she decided to open and drink some bottles of the wine that I bought while I was gone, and drank two of the very expensive bottles of wine. She is refusing to pay me back or buy replacements because “I always share” and she “shouldn’t have had to remember which were special” and I should have kept the gifts far from the “communal wine.”
The thing is, literally none of the wine is communal, because I am the only one buying it and I have been very upfront both about how (1) those bottles were gifts and (2) I really want her to start paying for the wine or just not drink it. I’m super angry and we had a pretty nasty fight. Am I being unreasonable? Did I train my roommate to walk all over me? Am I being a child because I won’t share? Is my friend being awful? Am I crazy? How can I make her understand that I need her to pay me back?