My local Starbucks offers a 10 cents discount and extra loyalty points for bringing your own cup. I've started bringing an insulated one that keeps coffee hot for longer & doesn't sweat with an iced beverage. I seldom see others bringing their own cups, even regulars I see there every week, even when Starbucks themselves sell reusable cups. It is almost like there is a weird stigma about handing the barista something that doesn't come from behind the counter. I encourage trying it, especially if you visit the same coffee shop habitually like I do.