Look at that old cruddy PHP code you worked on two years ago. You know what I’m talking about. Seriously, it’s only cruddy because you are two years wiser–two years more experienced. The site is still up–still maintainible.
Now, go learn Ruby and Rails…go learn .NET, J2EE or who knows what else. When you come back to PHP (and you will ;-)) you are going to crank out the meanest, slickest, hottest code you ever wrote.
That’s the lesson I liked so much: Never stop learning new ways to make the best tool for the job even better.