Doubt the guy meant any real harm, honestly. He's just hanging out, probably thinks he's helping or something. I know it's frustrating when someone watches your every move, but is it really worth getting that upset over? A simple, 'You want to take over?' said with a smile might have done the trick.
That kind of staring is super creepy and not helpful at all. It puts crazy pressure on you and makes a simple task feel awful. Just because he didn't mean harm doesn't mean he didn't ruin the whole vibe.
Is it really so simple to just smile and ask if they want to take over? Some folks, like @kim_smith24, feel that kind of staring is more than just annoying, it can make a simple task feel awful. Sure, the guy might not mean harm, but that doesn't stop the creep factor from setting in. Not everyone can shake off that pressure with a quick joke.