What is the opposite of "entitlement"?

I'm a bit lost; apologies for my rambling, and what might come across as a ridiculous level of unawareness.

To start at the beginning, I understand the popular usage of the term "entitlement". It's used in a context of people who feel they have a right to things when they actually don't, and such people are (in popular culture as I see it) generally agreed to be The Worst.

When I read up about it, I find articles that address the issue as levels of entitlement, starting at a baseline of "only feels they have a right to things they actually have a right to" and extending up to "thinks they own the universe".

It makes sense that this spectrum also extends downwards past the point of "no issues with entitlement", to a realm of people who have issues with not feeling entitled to things when they actually are. I'm assuming that the same general concept just changes name as it goes through the zero point, and there is probably lots of information out there if one knows what the right term is. So, my question is "what do you call this?"