The rewards to me are in the learning and the experiences I have that help me grow in my own learning both with others and alone.
Learning is the ultimate reward in life IMO: there are some things where you just suddenly go to a new level and reaching that level makes it all worth it.
I imagine all people value this kind of experience as equally important no matter what kind of division you can place on them.
I'd imagine for example, one of the things an emergency surgeon learns is that no matter if it's a victim that has been shot by a criminal or the criminal himself being wounded, they will both be treated. A lesson of learning what it's like to suppress your own ideas about what and wrong and then slowly learn the implications to me would be an experience well worth it.
In fact I imagine many of the unseen leaders of the world like the social workers, the teachers, the child carers, the lawyers who work in legal aid for lower socioeconomic classes and generally the people that for one reason or another deal with the situation of putting aside their prejudices and the crap they have to deal with from the person that is asking for help, and doing their job regardless.
I imagine a lot of these kinds of people get a kick out of the learning experience for one reason or another: for me mathematics is a way to learn about the world, about us, and about everything that is out there.
It is something that all trained people agree on and for that reason I think its universal and a good thing: it is based on a meritocracy and something where everyone has the same advantage. The arguments are debated, the definitions are agreed upon and the ground is therefore leveled.
It doesn't care about feelings, it doesn't seek to entertain, and it most important it doesn't involve an deception: it is what it is whether you like it or not. It doesn't care who you are: it remains the same regardless.
The other thing apart from the above is that there are far worse jobs out there where people bust their nut doing physical labor on minimum wage where they end up 10 years later being tough out of luck due to a back injury or at least a lot weaker, where-as you get an office job where the stress is mental (but at least you don't end up with a broken back and out of work).
The other thing is that a lot of the work out there is really horrible work: all the depressed people out there (even the high earners working crazy hours).
Finally, I am thankful in some ways that I have the opportunity to go to university: a lot of people are deprived an education and as a result they struggle and can never go where people like us go: to a university.
University does not define a person, but it gives them certain opportunities and I am thankful for that. I can't imagine what it's like to grow up in a country where people are not even given basic skills in comprehension let alone university level mathematics, and to know what some of these people have to go through in that respect helps humble me just that little bit better.
In a country like ours, I can't really think of much to complain about and the opportunities we have (even though I sometimes do).
