1. "Life is what happens to you while you're busy making other plans." -John Lennon
2. "How we spend our days is, of course, how we spend our lives." -Annie Dillard
These, of course, are different angles on the same thing.
Just recently, I've added another:
"Will you please start thinking that this is a good time now?" -some guy I met whose name I don't remember
I've decided that the first two are a good foundation and the last is the right rallying cry for the next year or so. Quit planning and start doing.