Your Model Aircraft speaks to you in "SIGN LANGUAGE", listen to it!
Awhile back I was flying my Super Skybolt (on its 159th flight) and shortly after takeoff I had noticed it needed a little down trim, so I gave it a click or two and everything was OK. I did a few aerobatics then it needed a little up trim and a couple clicks once again fixed it. By now I realize my airplane is TALKING to me and I really ought to land, and find out what's going on. While making a turn (to head back to the runway) the Skybolt went into a violent spin. I fought the airplane all the way down to the top of some trees when I barely managed to re-gain control. I gently limped the airplane to the runway and landed as quickly as possible. As it turns out, the servo tray completely broke loose. The servo tray holds the elevator, rudder, and throttle servo. All the controls on the servo tray were interacting with one another.
My airplane "told" me something was wrong as soon as I took off, but I ignored it. It "told" me again after some aerobatics that some thing wasn't right and I listened this time, but it was almost too late. The airplane really SHOUTED at me by throwing itself into a barely recoverable violent spin while making a turn. I was very fortunate "this time" and got it home in one piece.
Any time you have to make unuaual adjustments while flying... Your AIRCRAFT is talking to you, and you had better listen!