Voters can certainly be selfish, in the sense of wanting something that might conflict with the greater good. For example, I might not want a new sewage treatme

Voters can certainly be selfish, in the sense of wanting something that might conflict with the greater good. For example, I might not want a new sewage treatment plant in my neighborhood, even if that is what the greater metropolitan area needs. I might want NASA to keep open a local office even if that interferes with efficiency. And there's nothing irrational about voting. Maybe it is irrational to spend a lot of time reading about obscure candidates for assistant deputy dogcatcher, but you can just leave those choices blank if you want, and just vote on the things where you already have a strong opinion.