It's wrong to grab people.
Auston is at a party when he notices a guest, Bill, who is engrossed in a conversation, has a large wasp crawling on his shoulder.
Auston wants to get Bill's attention, so he can warn him of the wasp.
"Auston leans in and loudly says ""excuse me sir"" in the direction of Bill."
Auston reaches towards Bill and grab's Bill's upper arm and yanks it to get him to stop talking.
Bill looks back at Auston and sees him gesturing about the wasp and is glad Auston warned him of danger.
Bill is upset that Auston caused him pain and grabbed him so hard and is so angry that he doesn't notice the wasp which stings him.