every farang in earshot was probably thinking exactly the same. except maybe his fellow nutjobs.
I don't know what part of Astraya you're from but where I grew up, southwest Sydney, complaining was taken as a personal insult as well so we did the never go back approach. so no different for me here.
but in this case the issue was so trivial it wasn't worth complaining about at the time and certainly not worth denying the enterprise your return custom. for 30 baht maybe but not 4 baht, that's pure pettiness. or a sign of 'mental disintegration' as Steve Waugh was fond of saying.