The word "reward" here is doing some heavy lifting, especially since the above comment don't include it. Who is doing the rewarding and what is the reward? Is

The word "reward" here is doing some heavy lifting, especially since the above comment don't include it. Who is doing the rewarding and what is the reward? Is getting higher wages for doing longer hours at work a reward? Are vacation days rewards? Is it a reward to get higher paid if you do a night shift compared to a day shift?