Some of the first things that sprang into my head, starting with the most obvious...
Facebook
EVERYONE is already on Facebook. They have spent years building up their networks, adding photos, sharing memories. For some, Facebook has become a huge part of their daily routine, it's the first thing they check when they wake up and the last thing they check at night. For some, it's completely overtaken email as a method of communicating.
As kids, many of us were taught not to be "quitters". Whether it was your sports team, you were learning an instrument or you wanted to get down from the table before you finished your dinner... we've all been there and we've been taught the same thing.
One thing that I've realized is: it's equally important to know when to quit.
A few months ago, I read an article by matt mullenweg (the founder of wordpress) called "1.0 IS THE LONELIEST NUMBER". Its a great read, even for non-geeks, here's a quick quote...
This Song Happens On A Train is a song that I co-wrote with some friends - Daniel Slade & Sven Heidinga. We wrote and recorded the song in two days just to prove to ourselves that we could. It was "one of those things" that we had talked about doing for a while and that weekend it just all came together.