Back when I used to live in Mission (and used to eat meat more regularly), I would go to the Burger Inn about once a month. The reason I went there was because I would also do laundry about once a month and so while I was waiting for my clothes to dry, I would walk across the street to the Burger Inn and grab a burger.
Now, I wasn't one to get a massive burger so I would always have the quarter pounder with a cream soda and sweet potato fries. I love sweet potato fries and theirs are very tasty. Not too greasy and not too soggy either - just right. The burger was thick and juicy and very delicious.
If you're ever in Mission and wanna grab a quick bite, the Burger Inn is a good spot.