The word everyone is thinking of, but nobody has said is "utility". A "util" is a measurement (like an inch or a pound) that measures how useful you find something. Usually it is measured in "utils per dollar." Everyone finds utility in different places. If you hate hot dogs, then even though they are cheap, you don't find much utility there. If you're starving, haven't eaten for days, that hot dog would suddenly be PACKED with utility for you... the first would be FULL of utility, the second a little less, the third even less, etc.
Most of the people on the budget boards find utility in the feeling of monetary security. We find value in knowing we have a bit "tucked away". We value the peace of mind that gives us. We find more utility in feeling secure than we would in "blowing" that money on something... but, that said, we can also feel utility using the money for something we have saved for. But it's a balance. I could blow all my savings for that big trip abroad tomorrow, but I would not get much utility from it because I'd be fretting about my lost security, plus my children are too young to fully "get" the experience. When we do go, I want them to be old enough, and I want to
Example-since this is a Disney forum. People here really like Disney. And people on this sub-forum like a good deal. So people here find utility in visiting Disney for various reasons, and find extra utility in doing it in a way that fits their values. You want to RUIN a trip for most of us, come along with minimal preparations. Buy everything in the parks and then complain about the cost, complain about the lines, talk about how long you're going to be paying the credit card bill for this meal that you don't even really like... and don't forget to constantly mention how you don't even LIKE Disney stuff... you get the point... It is very possible for one person to completely drain the fun (utility) out of someone else's day-- if we let them.
In your case, your friend sounds like she finds utility in hanging on to her money, but she does it in such a way that makes the eating-out experience unpleasant for you. My question is, which one of you says "Let's go out to eat?"