Never happy!

But you have given them a vantage point and they feel duty bound to use it 

I bet they spend hours on that wall watching the world go by.  Mine have big logs in their runs and spend ages perched on them.  If Sevi is anything like my little horrors, he will wait until you are comfy in those chairs before jumping up on that wall to let rip.  I've given up trying to sit on the garden bench for a coffee if mine are out