To make blockchain more forgiving for human errors it's time to introduce the "undo" transaction.

This undo transaction can be issued up to 5 blocks from the original transaction, after which it is no longer possible.

In case of bitcoin this should give the user 50 minutes the time to issue the undo transaction, after the 6th confirmation of the original transaction it is no longer possible if the undo transaction was not included in the 2th, 3th, 4th, 5th, 6th block since the original transaction, being the 1th block.