Yes, too many us and thems. Both the ATCO and the commander of the aircraft concerned are obviously trying to ensure a safe operation, and actually they are working in a complementary manner. Both need to do a good job to ensure safety.
But, and this is no slight whatsoever on the ATCO, it is patently the aircraft commander's job to ensure his aircraft's safety, and he can legally override any ATC instruction in that endeavour.
Yes, there'll be an MOR and the whole matter will be looked into if he or she does defy an ATCO's instuction, but the pilot is the person in the aicrraft and it is logical that that person has to make the final decision. This final decision is, of course, nearly always to follow the ATCO's instruction, as the Commander knows that the ATCO is probably in a better position to make a decision on most relevant issues.
But not weather. If the Commander decides he must land off the approach and the ATCO says "go around" due weather (which should not happen in Britain), the Commander can exercise his prerogative knowing he is legally able to. Whether he was right to do so is a different matter, and this will be determined subsequently.
If I may make one comment about some of the aggressive ATCO responses (I assume they come from ATCOs, but they may not). Get that chip off your shoulder! You do a brilliant job and should be proud to be a part of a successful business, but pilots also do a pretty decent job over all, and both professions work as a team. Same comment to those snotty pilots who think they are God's gift to aviation.