Before They Were Stars: Robin Williams in a Phone Commercial

Here’s another clip Gill sent my way, a 1977 commercial for Illinois Bell featuring an unknown Robin Williams. In this ad, he goes phone shopping with his wife, but when you let Robin Williams loose in a phone store, you know he won’t be able to resist the urge to start picking up the receivers and speaking in funny voices. Why do I get the feeling that Robin Williams really does this every time he goes phone shopping until security removes him from the store?