We often frequent McDonald's when we travel, because It's usually consistent. But in both Thailand and Malaysia we have left a McDonald's location with nothing.
We tried to order a grill item without mustard and Mayo. They could not understand and couldn't find anyone that could. So we left, frustrated, vowing never to return. I understand we are in a foreign country, but that being said, I have no problems getting what I want at KFC, Papa John's, Pizza Hut, Subway, Wendy's.
On many occasions I have gotten unwanted items on burger, back in North American.
I if you have tried to email a complaint to McDonald's, they only allow phone, letters or fax. That is a clear sign, they really don't care about customers complaints.
Product or Service Mentioned: Mcdonalds Burger.