Random Thoughts: why proselytizing is a bad idea

So I was watching a re-run of 30 Rock, and one of the characters sang a song, "Oh everybody born before Jesus is in hell." 

Funny, ha ha. However before I knew it, my warped mind went into action and started over thinking it. So, next time I'm approached by someone trying to preach Christianity to me (and boy, do I get a lot of those), I should jump into a lively debate with them.

Me: So what you're saying is that I'll go heaven if I adopt Jesus as my saviour?

Religious guy: Absolutely.

Me: So what about my parents? They're Buddhist. So, they'll go to hell?

Religious guy: Errm, well...

Me: What about my grandparents? Or my ancestors?

Religious guy: Well, you see...

Me: Is this why the Romans killed so many Christians, because they were basically saying that all their loved ones were condemned to burn for all eternity?

Religious guy: Ahhh...

Me: Why doesn't Jesus swoop down from the clouds and hadouken everyone?