I have heard of this "tail wind" phenomena, but have never experienced it.

There have been days when I've spent all morning feeling like I'm riding through molasses such was the force of the headwind, but stayed positive by telling myself "It's OK, this will be a tail wind on the way home". Then, right at the point I turn around, every branch, every flag, every blade of grass suddenly snaps to attention and begins to lean the other way. More than once I have caused heads to turn by yelling out in frustration.

In my book, "training" is something you do because you have to, not because you want to.