Bill J wrote:
Yesterday I was on an IFR flight about 50 miles from destination. The
area was getting covered with TS, including my alternate 20 miles futher
west. Home base was 150 mi to the east. I realized I might have to
reverse course to escape, but did not have enough fuel to get home for sure.

So, the last chance to land before the TS got heavy was coming close.
When about 15 miles from this new "alternate" I told controller I wanted
to change destination.

Good move. The combination of convective activity, deteriorating
weather, and an unsure fuel situation is not fun. But you knew that :-)

I expect a vector to the final, and I was needing
to start descent. Nothing happened. Finally when maybe 5 miles out, and
way to close to get a vector, controller quizzed me with "I need to know
what is the reason for the change in destination??

It's bizarre that he should even ask this, but don't let it get to you.
The only thing I can think of is he suspects you're in some kind of
trouble and is trying to figure out if he should handle you as an
emergency. Tell him something that'll make him happy, and get on with
flying the airplane. Tell him you're diverting due to weather. Declare
minimum fuel if you think it'll make a difference. If he's not taking
the hint, just tell him straight out what you need, "Request clearance
to Podunk Municipal and vectors to the ILS". If he's still not taking
the hint, request immediate clearance.

From the tone of voice I could tell I caused him a problem.

OK, so you caused him a problem. Bummer. He can go home after his
shift and bitch at his wife about the bad day he had at the office. Not
your problem. Your problem is to get some more fuel, and unless you're
flying something a lot fancier than most of us, that means landing at an
airport.