I think it's important to relax and not stress about putting words on the page, especially when writing something so personal.
I thought about all of my vet experiences, chose the one I thought would be the most interesting and most fun to write about, and started with that. My first paragraph was essentially an account of a super cool case I helped with, and then I delved into how that one case is just a single experience out of hundreds that have shaped me into the pre-vet I am today. I then discussed my three favorite merits of veterinary medicine learned through those varied experiences; giving examples of my encounters with each and how I intend to develop those merits in my future career. Writing about the case at the beginning really got me pumped up to write the rest, because it reminded me how much I want to pursue this field. I had fun with it, but not in a toungue in cheek, or trying to be humorous kind of way, in a "this is really my passion, and I enjoy writing about it" kind of way. If that makes any sense 😳
Now, if you've seen my post in the successful applicants thread, you know I had quite a few negatives worth explaining. I didn't do it in my personal statement. Some say you should, some say you shouldn't. To me, it just didn't fit. I didn't set out with a decision either way, but in the end it just never came up. So I just put all of that into the explanation statement.