Agree with everyone else, let him do it, be patient and (I don't mean this in a horrible way) be grateful. My ds has dyspraxia and at 3 and a half still takes longer than your ds to get in the car and is a LOT heavier to lift! I don't think your ds is testing boundaries, I think he's simply wanting to do stuff himself and needs to practise - like we all do. I realise how frustrating it is atm (my life is like that!), but soon it will be fantastic as he will be able to dress himself, get his own milk (!!! WOW!) and your life will be so much easier. I also think telling him to hurry is pointless. I do it myself with my ds when I get frustrated with him, but he's doing his best and tbh I feel like a bully when I'm nagging him. I'd hate it if someone talked to me like that. Just to reiterate, I sympathise, I'm not criticising, and I do the same, but I'm a year further down the line and I WISH my ds was more physically independent (and I'm also lucky compared to many).