The best way to avoid getting stale is to keep learning -- new songs, new techniques, etc. There will be times when your playing is less than inspired (that's true for all of us), but if you keep refreshing the material and developing your skills, the dry periods shouldn't last too long. Also, continue to seek out other people to play with -- it expands your consciousness (without the need for chemical enhancement), and helps keep things from getting too predictable.

Rick sounds like an excellent teacher, but I wouldn't stress too much about the pitfalls he identifies. It's good to know they're there, but you can get past them.