I said that I "tend to avoid" restaurants that don't take Amex, not that I flatly refuse to eat at any of them. I see it as somewhat of an indication that the restaurant is not very customer service oriented which often spills over into the overall dining experience. I know some restaurants may view the situation as "Amex charges too much of a percentage" instead of thinking: "There may be some customers who won't dine here at all if we don't accept the card they have in their wallet/purse". If I find that a restaurant has SIGNIFICANTLY better food and service than its competitors, then I will eat there even if they don't accept any credit cards. I have rarely found this to be the case, however.