I agree with the stated view here that it is the tone of voice that makes a difference but a particular experience showed me how entrenched in Thai attitude the word is. A grandfather on his motorbike and sidecar crossed two lanes of traffic to where I was standing in order to teach his young granddaughter what a farang is. The pointing that went with the little girl's 'education' was, surely by any standard, very rude. Sorry but I'm unlikely to "get over it".