I'd suggest distraction too - it's a very powerful tool!

I also hate having those days where I feel like I'm always saying "no" or "ah" (usually the latter). Some days I feel like I'm saying it endlessly too and of course the more it's said, the worse Jacob's behaviour can become at times! So to counteract that I try and use the word "yes" or "good boy" or some other praise for things that he's doing that are positive behaviours....it might be something really simple, but to him, he's getting that positive reinforcement and praise....and it's so much nicer for everybody to hear!