It's good to see the two sides to the problem;
A couple of years back we were heading towards LANAK on our way to EGPF. Over the top of LANAK was a red paint on the wx radar. The Scottish controller was working at least at his peak, possibly just over the curve and getting overloaded. He was working lots of traffic with constant RT. We were told to hold at LANAK and requested holding over the GOW due wx. Refused. Couple of miles later and asked again, this time told (vehemently to hold at LANAK). Entered the hold in turbulence and was struck by lightening 3 times in the first hold. At that point we exited the hold towards the west and then told the controller that we were on a heading to avoid. So you can't win, just try what you can to comply. What we must all remember here is that the captain has the ultimate responsibility for the safety of his aircraft and when he deems it necessary he can make the decision not to follow an ATC instruction. It's all down to risk assessment and with TCAS the commander has a reasonable chance of disobeying an ATC instruction yet still keeping separation from other traffic. I felt the incident in question had a lot to do with the controller being overloaded and literally just trying to hold everything together as he did not have sufficient capacity left for 'alternatives.'
To close I would like to offer my thanks to all those ATCOs who do such a great job day in day out, especially London sector controllers who's capacity and professionalism often get the pair of us looking at each and remarking "they're busy!" when what we really mean is "how the hell do they cope with this workload?"
Thanks again
PP