Costco comes to mind with force. The idea that everything you purchase is eligible for return (even half-eaten food) gives a customer confidence to buy easily with no concern. Furthermore, their return process is so easy and doesn’t even require a reason or receipt and they credit you instantly for your purchase with no questions asked.
Friction is where you have to shop somewhere and see a sale or promotion, but when you reach the register or checkout, it doesn’t recognize the promotional price or discount. This requires extra work, brings about aggravation to the customer and at times can lead to a lost sale as the customer isn’t willing to deal with waiting for a solution from the merchant.