I am sorry to say I happened to confuse diverse levers in diverse types of gliders in the past.
* I once pulled back on the release lever (it's not a knob, it really looks like an airbrake lever) instead of opening the spoilers in a Rhönlerche;
* I did the same with the flaps instead of the airbrakes in a L-13 Blanik;
* I put the flaps from positive to negative instead of closing the airbrakes on a Janus during finals when the airspeed became too low (that one allmost crashed the glider, I corrected my mistake at the very last moment; the situation arose while my pupil in front was making an approach with braking parachute, full positive flaps and full airbrakes, and was slow in closing the airbrakes when I asked him to do so to maintain airspeed - of course, I should have had the left hand on one of the levers, but I wasn't ready, being too confident in the abilities of my pupil).

The levers I wrongly used had a common characteristic: they were the upper, what you could call the "most obvious", lever. When under stress, that's where your hand is going automatically.

I really think, from a safety point of view, that the "most critical" lever should also be the "most obvious" lever. In my book, that's the airbrake lever. I don't like the ergonomics of the levers you have to rotate to be able to use.