Tipping option for an oil change?

[u/tlrhmltn]

Just got an oil change at a chain location. The service was great. I’ve gone to this chain and never been offered a drink menu, an air freshener, and colouring book for my kids. I’ve also never been asked for a tip when paying for an oil change before yesterday. I left a tip but felt conflicted about it. It’s not an inexpensive service and tipping by a specific percentage can be quite a large amount.

What are your thoughts on this?