My wife has a habit that drives me a little crazy. If I have a drink that contains any booze, she drinks a bunch of it. If I'm eating something that tastes good, she eats a fair amount of it.
I'd expect this to happen some of the time, but it's almost constant. So why would I care about an activity that could be interpreted from the outside as sociable? For starters, if I'm drinking a beer I like to have the bottle not disappear the second I set it down or right before I want to pick it up. Also, if I have a beer, I actually like to drink the whole thing -- I'm not into half servings. If I'm cooking dinner, I like to know how much of stuff to make. If I'm led to believe she won't eat any of something, I'd just as soon not be starved afterwards because I had to cut my portions way down.
Since I know this happens, I often say something to the effect of "how about I grab you a beer? you want me to make you a little ....?, etc" and the answer is always no, even if I push the issue. I've brought it up on a number of occasions since I'm happy to get her whatever it is I'm enjoying. This happens at restaurants too.
From what I can tell, the logic is partly that the calories don't count if they start out with me. But that's not the whole story because she insists that I don't load up for two when I'm getting something for myself. What gives?