SAQ personal statement

Hi, I'm apply to study geography at Clare College. My original personal statement was very specific to geography and Cambridge say on the guide to completing the SAQ that not writing anything in the additional personal stament box on the SAQ will not disadvantage your application. I was just wondering if most people have? should I anyway? What kind of things have people included?

Here's what a Cambridge AT recommends in their current thread:
http://www.thestudentroom.co.uk/showthread.php?t=4327946&p=67985638&page=23&highlight=optional#post67985638