Running burnout.
There's two words that do not fit together very nicely, am I right?
Thankfully, I don't think I've ever truly suffered from said burnout. There have been times, though, when I have needed to scale things back a bit and/or shift my focus. There may also have been some goals that got modified along the way as well.
All of which has been fine and dandy. After all, I'm still running.