Because your pay comes from taxes

You work for the government.

Sometimes what you do seems important. Sometimes it doesn’t.

Sometimes you wish that you made shoes. People would come into your shoe store. If they liked your shoes, they’d buy them. If they didn’t, they wouldn’t. No one would give you their hard-earned money unless they really wanted your shoes. As long as your shoes were selling, you’d know for sure that your work was making the world a better place.

It’s not like that with your work for the government. People have to pay for what you do whether they like it or not. If they didn’t give you their hard-earned money, they’d be prosecuted for non-payment of taxes. If they persisted in their refusal to pay your salary, people with guns would show up and take them to prison. You have no way of knowing whether your work makes the world a better place.

Sometimes you have a suspicion that it does not. Sometimes you have a feeling that you’re simply extorting money from other people.