You have to pick your battles, and if taking a stand, be consistant. If you pick out blue shoes and he wants black, does it really matter? If he eats potatoes with ketchup instead of gravy, does it matter?
When my kids won't get dressed, I put them in the car as is, and make them get dressed when we get there. If we only have milk and they want OJ, then they get nothing until they're ready for milk. Usually, if I put the milk back in the fridge, after a few minutes, they are asking for it.
Ex. I was taking my kids on an impromptu Santa picture visit. My 7yr old had just lost his 2 front teeth, and I was taking him to see Santa to ask for them for Christmas. I didn't get them all dressed up becuase I was taking the approach that if I did, either the line would be really long, there'd be a melt down, etc. So I asked my 7 yr old to go put on something nice, we were going to the mall. He came down in a bright orange, Dukes of Hazzard General Lee '01' hoodie. Words were exchanged about whether that was appropriate. He wouldn't budge. So I said fine, its your Christmas pic that's going out to all of the family. He said fine. We went, got the pic taken.
He is super proud of the pic. Most of the family loves it. Says that its so him. The others not so much, because of the Orange hoodie. I picked my battle. If I had argued, I'd still be sitting at the house, without any kind of pic.
M.