it will hapen one day.... thrust me

I am a very very careful modeler. I build planes since 20 years
and it hapened to me also last year . Reversed ailerons on a maiden flight....
this hapened to me because I had to solve some minor flight controls troubles and I simply reversed one of my aileron servo.

In real live, I fly a wide body, we are 3 in the cockpit and I may tell you that somethime we all 3 simply "forget" to check some very important parameters, simply because we are too relax and too confident....
We are humans