My usual trails have a slight grade to them, so I battle the grade more than the wind, but a headwind when going down grade does suck some of the fun out of it.

I tend to do out & back rides, starting the hard direction, and cruising back... so I understand the feeling.

Also, one of my favorite trails has a bike rental company that also provides a shuttle service that will bring me back to the car for $19.95 (or a season pass for $99, which I have) so I can ride 10-36 miles down and get a ride back. Those are my most pleasant rides. Well worth the $5-10 per ride I willl end up paying by the end of the year.