Dumb ideas I should maybe have patented

Some years ago I had an idea for combining a pair of electric hair-cutting clippers with a vacuum cleaner, to produce a hair cutting tool which would suck all the cut hair away rather than depositing it all over you. It’d also work in zero-G, and if you put appropriate attachments on the front you could cut hair to set lengths just by running the hand-held nozzle bit over your head.