Interestingly all 4 had different brake lever change mechanisms for the gears and momentarily forgetting which bike I am on when climbing does quickly concentrate the mind.
I have 4 bikes (only 3 currently in use )
One is a fixie - no trouble, as Brett says "Fix your wheel and free your mind"
The Sportive has Ultegra STI.
The 'crosser (currently mothballed) and the monster cross are both XT 3x9 with bar end shifters.