Climbing the stairs

Cam is a perfectionist, he won't show us a new trick until he is sure he can do it properly. Case and point the stairs. For a couple of weeks we have been trying to encourage him to climb the stairs but he would much rather sit and swing the stair gate then put any effort in. That was until tonight. Mummy was in charge of bedtime for a rare treat and decided to give it another go. This time he zipped up the stairs as if it was the most natural thing in the world to do. What happened to the need to practise things?