We always try to time working cattle so that our neighbors won't drop in and try to 'help'. They (the cows!) are used to us, and we can separate them easily, walking through the group... makes such a difference. Very little hollerin and so forth...
I usually work up by the head chute, getting them on down the alley, giving shots, tags, worming, whatever. One day our really 'helpful' neighbor decided that we needed him. My husband and I were doing fine, and he stepped in to 'take over' moving them down the chute. He turned to me and said, "Just stand over there and look pretty."
I didn't stand still long... just kinda ignored him, and he finally decided that he'd helped out enough. The cows reacted differently to him than us - really aggravating!