I hate these questions too. For those that require three comments, I usually comment about a couple of aspects in each one, such as ease of parking, friendliness of staff, the restroom, product selection, store layout, etc. So basically one comment broken into three parts. Generally, I have found filling in the comments goes quicker if I jot down a few unique things about a station while I am doing the shop, so I don't have to rack my brain as much to think of something. Like, the clerk said hello when I walked in, the walls had attractive graphics, the entrance area was open and inviting, etc.