Friday Thread: What's the worst piece of running advice you've ever received?

Last December, we had a really fascinating discussion about the best piece of running advice you’ve ever heard, which elicited so many great comments from each of you (that I learned a tremendous amount from too).

So I’d like to turn the tables a little today and ask, what’s the worst piece of running advice you’ve ever heard? Or, a piece of advice you got and tried out, and then figured out you actually needed to do completely differently to make it work for you?