I'm a toothpaste last-bit-squeezer for sure. It's not loss aversion -- it's waste aversion. There's probably lots of reasons why I don't like to see things wasted, including social, or family upbringing, or personality. But I have the same impulses with food, clothes, computers, almost everything.
I don't always buy food in bulk to save on cost, or look for the best deals, but whatever I have bought I try my best not to waste. It's irresponsible. Maybe in some ways I feel it's bad for the environment, or sets a bad precedent for how I think people should behave. I don't mind what sort of things you choose to buy or like, but I would prefer you don't waste them.
Resources of all kinds are limited, so making the most of what we have is an important principle, at least for me. Sometimes it's silly -- eg. I really should replace those old socks with holes in them, I can definitely afford new ones, but if something can do a bit more before being thrown away or replaced, I'll try and get that much more out of it.