The case of the missing key

I'm sorry, i do not care what anyone says, i am not an irresponsible person. I look after my belongings and take care in what i do.

Let me explain my sequence of events. Maybe you are able to pick up on the moments when i could have in fact miss-layed my key. Bike key that is.

Tuesday was the last time i used my bike. I cycled into town (accompanied by my key) . Dismounted my Bike, locked it up and went to H&M followed by the post office. Unlocked my bike (therefore i must have still had my key by this point) Remounted my bike and cycled home. Now, when i unlock my bike i slip the key back into my coat pocket. Every time. Without fail. So why, may i ask, when i slip my coat on this evening, retrieve my bike from the garden shed and wheel it into the house, do i place my hand in my pocket to find an empty one? No, i don't know either.

Any suggestions?