For clarity, I am fully aware of how keys work and that's not the question but:
I have a drawer full of keys that I have entirely forgotten the purpose of but absolutely cannot throw away just in case I am ever presented with a lock I can't unlock because I threw the key away.
I know at least 3 of them are for a property I haven't lived in for over 2 years. One is for a bike lock I no longer own and two are for padlocks far lost in the mists of time. I just can't throw them away though!
Please tell me it's not just me who has this.