LPT: Ask to speak to the manager when you're actually happy with your service. Management rarely gets positive feedback and it can make a big difference to the person that helped you.
I worked in customer service related positions for nearly 20 years, including more than a decade as a manager. It is almost a given that anytime someone asks to speak to the manager. It is because something has gone wrong or the staff member helping them was rude or otherwise they just had a negative experience.
Of course, negative feedback. He is useful to help ensure problems, get solved and problem. People don't continue to work for the company. But, there is a strong bias toward the negative which means that positive feedback often doesn't get submitted. People tend to ignore the endless requests for scan the QR code and fill out the survey or touch the kiosk screen after you swipe your card and tell us how we did type stuff. So what this means is highly talented workers often don't get recognition for how good they are.
You will absolutely make someone's day if you ask to speak to their manager and you let the manager know that they did a great job. Not only that, but a lot of companies have incentive programs that are based around receiving customer compliments, so it's entirely possible that you will cause that person to get a free meal or a gift card or the positive marks will be reflected at their next review and their raise will be higher.
Also not gonna lie, there's always this little moment of panic that comes over someone's face when you ask to speak to their manager and they know beyond the shadow of a doubt they did a good job, and it's a little funny to see their reaction when they realize no, you don't have a problem with them, it's all good, and they usually laugh or smile.