I was up with DS1 (3.5) a lot in the night, spent the rest of it asleep on his floor, so I'm tired and grumpy (and impatient etc...)
I was getting him ready for nursery (as well as DS - 2, who I get ready to leave, turn around & he's taken of his shoes for the 5th time) barking orders at them, swung DS1 around so he would sit on the step to get his shoes on & he stumbled into the wall. He was upset. I said "can't you just listen to me, DS1?" and he said "can you not just be nice to me please?" Gutted 
He's now at nursery & DS2 is in bed & I feel so sad & guilty. I love that beautiful child more than anything in the world, why can't I just be nice to him?