Yesterday was a beautiful clear day, unlike almost every other day this year and I flew my Phantom 4 in a 12 mph wind with gusts to 22.  I was flying over the lake and was curious about a wind assisted top speed.  I flipped the switch to Sport mode and flew with the wind to over 50 mph.  When I stopped I meant to go back to the normal flying mode and moved the switch.  The Phantom should have been stationary, but it was moving away from me fairly rapidly.   I tried turning the Phantom which it did, but it kept moving away from me at which time I must admit to a little anxiety.  I pressed RTH with no success.  At this point I was thinking the Phantom was uncontrollably heading out over the lake and I might not see it again.  This is when I looked at the controller and realized I'd not switched it back to normal but mistakenly moved the switch to the ATTI position, where there is not GPS stabilization, if I understand the setting correctly.  This is when I realized it didn't know where home was and what I thought was loss of control was the wind blowing my Phantom to a certain dunking and loss.
After switching back to the normal position and gaining control, it flew back as it was supposed to.
What I realized and was the learning experience, was that even though I have hundreds of flights, I made an error by moving the switch the wrong way and was positive that the Phantom was going off on it's own.  My first thought was a malfunction rather than pilot error.  I should have calmly taken the time to check the screen and look the switch settings rather than getting into a minor panic - the first stage of a major panic.  I wonder how many of the fly aways or other "unexplained" flight experiences are due to similiar pilot errors that could be corrected by a calm verification of settings?

No harm, now foul. I did the same thing about 16ft away from the edge of a building and it went hurtling towards a stone wall. I have all of 3 seconds to realise my mistake and correct it in time. I don't use ATTI for flight, but whenever I'm going to be pushing the boat out in distance, I always flick over to ATTI now to monitor real world wind speed and direction.

I hear you on this one.  Similar incidents have given me bursts of anxiety as well.  I now have an quick emergency process for incidents like this :

1. push switch to assure the AC is in P mode,
2. gain altitude, to get above all obstacles,
3. press the pause button on the right side of the controller, to pause any auto flight modes (e.g. POI),  
4. check to see if I am back in control.

I complete steps 1 - 3 as fast and as accurate as I can.  Saved a few trees this way.

Nice save TimmysDad!  Keep Calm & Drone On Safety First! Ken.

"I wonder how many of the fly aways or other "unexplained" flight experiences are due to similiar pilot errors that could be corrected by a calm verification of settings?"

Most of them.

You usually learn more from any lesson that comes with a shot of adrenaline.
The message sinks in so much better.