He encounters a Christian man who comes to evangelize him (Penn calls is "proselytizing", but it is really evangelizing). The man left an impression on Penn that lasts.
In turn, this video has made a profound impact on the way I evangelize. This is the money quote:
"If you believe that there’s a heaven and hell, and that people could be going to hell or not getting eternal life or whatever, and you think that it’s not really worth telling them this because it would make it socially awkward - and atheists who think that people shouldn’t proselytize ‘just leave me alone, keep your religion to yourself,’ - how much do you have to hate somebody to not proselytize?"I mention this when I talk about evangelization.
"How much do you have to hate somebody to believe that everlasting life is possible, and not tell them that?"
Watch Penn for yourself: