Me: The first victim of the best con-man is himself.
(I say this as someone who has been conned.)
Holden Karnofsky (of Open Phil; emphasis added):
Most of what I believe is mostly based on trusting other people.
• I brush my teeth twice a day, even though I've never read a study on the effects of brushing one's teeth, never tried to see what happens when I don't brush my teeth, and have no idea what's in toothpaste. It seems like most reasonable-seeming people think it's worth brushing your teeth, and that's about the only reason I do it.
• I believe climate change is real and important, and that official forecasts of it are probably reasonably close to the best one can do. I have read a bunch of arguments and counterarguments about this, but ultimately I couldn't tell you much about how the climatologists' models actually work, or specifically what is wrong with the various skeptical points people raise. Most of my belief in climate change comes from noticing who is on each side of the argument and how they argue, not what they say. So it comes mostly from deciding whom to trust.
I think it's completely reasonable to form the vast majority of one's beliefs based on trust like this. I don't really think there's any alternative.