Why do people forward heartwarming "true" stories and amazing "actual" photos in e-mail?

We all get them, from otherwise intelligent, sensible individuals. The “true” story of the grieving father who wrote “Taps” during the civil war, or the “amazing” photo of the lightning bolt next to the tornado and oil rig, or the “incredible” music-machine in the basement of MIT… These are usually multiple “forwards” with lots of !!!!!. They are also forwarded by people who don’t know how to BCC. Given how simple it is to look up and verify things via Google, etc., why do you suppose these persist?