Growing old sucks....Consider the alternative.
Allegedly representative democracy sucks.....Consider the alternatives. (Caveat: with the internet, the Athenian democracy model is a possibility, both scary and reassuring.)
Not giving up on politics sucks....Consider the alternative.
Also, some of us recklessly had children and/or grandchildren and want to see them grow up with breathable air, potable water and nutritious food.
In answer to your other question, we get the best candidates money can buy. Sometimes, I blame voters. Sometimes, I blame everything but, including the dumbing down of Americans.
It also helps to be be ready for call and response.
Call: "Voting is too much work."
Response: "Can I help you request an absentee ballot?"
Call: "people forced to live on welfare are lazy and I'm going to make you listen to an vitriolic diatribe abt my problems with them which are really to do with my employer being a cheap bastard and not the fact that some people are sick or disabled and still need to eat"
Response: I agree with you that poverty among working people is a huge problem. With Medicaid, food stamps, we are subsidizing companies that don't pay their employees enough. As Sanders says, no one who works full time should have to live below the poverty line. I also agree with you that wealth and income are not distributed fairly. Let me tell you how Sanders proposes to make America more fair for you and the rest of the 99% of Americans.
Call: Doorslam
Response: slide a leaflt under the door.