It sounds like he wants some control over his environment, now that he's a 'big guy'. 6 is 1st grade. He's in "real" school. So he has people telling him what to do and big time responsibilities on every end. Now is a GREAT time to let him start making some (limited) decisions.
What is he asking to do that he is being told "no as usual"? You mention getting dressed and eating -
You may do this already, but are there things you can let him decide or maybe just alter your phrasing -"do you want to take a shower before or after you do your homework?"
"do you want to get dressed before you eat breakfast or before you brush your teeth?"
I also would let my daughter "decide" the veggie for the night (or type of pasta, or what goes in the salad) and then she got to help fix it. So, "should we have green beans or peas?" then she would go get them out of the fridge and wash them, put them in the bowl etc.
As far as the field day - I would just ask him what would have made the day more fun for him, and see what he says.