I used to be a greeter - think of it this way - do you play chess so that someone else can let you play poorly, or you want good competition? I do understand playing nicely, but while you are winning, take the time to tell them about the site, and possibly make a new friend. They shouldn't hold the loss against you
As a greeter, do you play to win?


Well, in a ways, people can't always appreciate a good tail-whooping.
I remember my first club director keep warning me (we were a pretty weak club, given that I was one of their better players!) to go easy on newcomers and I really had a problem understanding why until I realized that many of them didn't show up the week after.
You just can't promote a game or get a crowd to be part of something if you don't make that extra effort to welcome them in.
Beyond the selfless reasons of wanting to get more people fired up and excited about chess, clubs (and I'm sure chess.com) may benefit financially and this in turn makes it better for everyone, good players or not.
Birdbrain is right: You don't have to throw the game, but tell them about the site, compliment them on the things that they got right, send them a trophy or a nice message afterwards.

Most of the greeter games end with timeout anyways when the newcomers find the joys of live chess. I use them for practice while it lasts. :)

I was refering to ridicule by play not verbbaly.
Beat your opponent by all means (if you can, I think I've played a couple and lost to them) but do it as quickly and efficiently as possible rather than promoting all your pawns to Queens and making your opponent look silly.

I've "played" over 1200 greeter games over the last several months, and what I've found is that if the people are interested in those games they will usually pick up several other games immediately, so it's just as likely that they will have already played and won/lost to someone else. Or they've played a bunch of live games, most of the people I get are already in live chess before they make a move, if they ever do. As somone else said if you play these greeter games regularly, you're lucky if 1 in 5 people actually play past the first move, so I always play every game the best I can. I use it as a learning tool for myself, to try out things I might not do in a rated game.
I've made only a handful of friends in over 300 greeter games. It's a worthwhile experience nevertheless.
Is chess.com ever in need of more greeters?
How do you become a greeter?
The option is at the bottom of this page.