OMG it's been so long! I will try to never be away from you all that long again! Okay! Here we go!
As usual, read it all here first.
LW#1: Sister wants YOU to take time out and pay to ship her gifts? I see why you are upset. No need to pile on the "we are professionals" here, just when your sister says something patently crazy, call her out with a laugh and a "that's crazytalk." If she repeats herself, say, "Look, the post office? We'll give you a ride there on Dec. 26." Yes, they were open.
Telling her that you're willing to share the inconvenience that way is about as good as you can do, and that she's awfully demanding, isn't she?
LW#2: Well, you only started seriously dating her a month ago. Look, is this the kind of person you want to be with? And moreover, is this the kind of person you want to be? Suspicious, jealous and trying to make her give up gifts that are just lotion and perfume (hey, the fact that he knows what she likes probably means bupkis, if that means anything to you. These are superbasic gifts for chicks). Sure, she's kind of weird about these gifts, and that means, I think, more than the whole tension you're creating around them in and of themselves.
I don't get what all her church talk or "he's married" talk is about, but let's face it, you've been in this thing a month and already you sense she has checked out. Nothing at all you can do about that, dude.
LW#3: So they breached etiquette, that's what a-holes do.
Now you are both totally aware that they are big a-holes. I don't see why you need to go all crazy doubling down on the number of a-holes in the family by refusing to see them for Christmas.
Besides, these are an aunt and uncle, fairly peripheral to the people you will be seeing. And EVERYBODY has an a-hole relative they don't want to see. Just ask around the Fray.
Your best bet is to shrug your shoulders, realize that you cannot control nor reform these a-holes, and move along in your own lives with as much dignity and grace as you personally can muster and not take things so personal.
LW#4: She hates you out loud, and you act your hatred of her out passive-aggresive style. Great.
I mean, as long as you realize that what you are doing is an act of malicious spite, as long as you realize that what you are doing will do nothing to thaw out your frosty relationship with this woman and do everything to make it colder. As long as you realize that your special someone is going to have to be the filter for this negative two way hatred, a position I'm sure she'll just freaking love, then go ahead, put your feelings in that locked metal box.
I mean, don't feel obligated to be the better person just because you want to show your honey that you aren't going to let her mother hate you for foolish reasons only, and not any actual behavior on your part.
I doubt you'd call this wrapping a "masterpiece" if you hadn't heard some cartoon villain use it before.
Besides, she isn't in on the longstanding years of prank wrapping.
Give people a break. They may give you one in return, awesome rich prankster dude.