Giving away a large cardboard box full of classic roadie stuff just before it all became 'collectors items'. Mafac brakes, original TA crank set, Williams alloy cotterless chainset, Balilla brake levers, Unica saddles, GB handlebars, Ambrosio stems - and more.
At least I know they went to a good and appreciative home - but I'd rather they were still in my shed!
Oh, and selling all my bikes bar one (6 road and track and a racing tandem) 20 years ago when my GP told me to stop cycling after a serious illness and then my specialist telling me it was the best thing I could be doing. At least it got me into mountain biking which I probably would have ignored if I'd stayed with road racing.