In the scope of a happy life, a messy desk or an overstuffed coat closet is a trivial thing, yet I find - and I hear from other people that they agree - that getting rid of clutter gives a disproportionat e boost to happiness.
In my house there's this light switch that doesn't do anything. Every so often, I would flick it on and off just to check. Yesterday, I got a call from a woman in Germany. She said 'cut it out'