Bitcoins can never be destroyed, the blockchain knows they are yours and will not forget. Like an omniscient overlord, the bitcoin network will be passing around blocks containing records of your bitcoin earnings long after you are dead. You can only choose to spend them or not. Your wallet only allows you to send them to someone else. They will be looming over you like a spectre of guilt, robbing you of your life essence, until you are destitute from your new obsession - sleeping in a cardboard box outside the loading bay of your former employer, hoping that you can get a tossed out hard drive to recover a wallet from, but alas, you will find no relief from your self-inflicted burden.