He was the sweetest kid in the world:

 I was full of hair.   No receding hairline, no thinning hair.  Nice hair, blowing in the wind.

Then he got a bit older:

My smile was replaced by stress zits.  By now I had a receding hairline.  And then he got older:

He turned into a 'tank', as my neighbour calls him.  By now my hair is gone, the dining table is broken, hardwood is scratched up (as are his sibling's faces). 

And he is only two!!! :| :| :|.