I've never given any shop a ten. With that being said, i have given many nines and eights, hardly anything lower. I take into account the location and its amount of potential business.
Meaning, the location could be on a busy highway or limited access highway where there are so many customers that it becomes difficult for the attendants to keep up with the resultant customer messes. I'm looking for signs of neglect and indifference, not a bunch of garbage that appears to be from very recent customers.
For the exterior, where there could be factors that the attendant has no control of, I won't mark them lower for obvious weather related things such as garbage in the forecourt after or during the winter versus summer, spring and fall when clearly, someone could be out cleaning up the area. The same goes for areas needing repair but that cannot be performed due to the weather. I report them, but they are not a factor in the rating.
As for the conduct of the attendant on duty, to me, that is a very critical matter. If they're cheerful, helpful and friendly, it does make a difference versus a crabby, indifferent or foul-mouthed employee (who I do report in my comments).
For the most part, I've found that it is the quarterly shops that exhibit the worst problems. That is where I find attendants in street clothes, dirty restrooms and cranky, bitchy attendants.
Recently, I passed by a station that I did quarterly. In the past, it has received my lowest rating for obvious neglect such as peeling canopy, rusty and peeling curbs and garbage littered forecourt. Although the attendant was cheerful and kind, she wore no uniform or nametag. To top it off, the owner would come out and harass me, with statements like, what the he!! are you doing here?" or "this so d@mned stupid".
Needless to say, I reported all of that in the comment section, also advising that I didn't want to go back there again (this was after numerous times of being besieged by the owner). I was begged to go back with a substantial incentive.
That was the last time I did it. I reported all of the same infractions and the owner being a complete @ss.
When I passed by recently, I noted that the canopy was gone, the pumps removed and the mid gone. It was now a liquor store and gambling joint. The owner was standing outside.
Being a good Christian, I honked my horn, gave him the peace sign and smiled.
Silently, I said, "Bite me you Mamaluke!"