Clerk in a Drugstore

John was a clerk in a small drugstore but he was not much of a salesman. He could never find the item the customer wanted. Bob, the owner, had had about enough and warned John that the next sale he missed would be his last.

Just then a man came in coughing and asked John for their best cough syrup. Try as he might, 

John could not find the cough syrup. Remembering Bob's warning he sold the man a box of Ex-Lax and told him to take it all at once. The customer did as John said and then walked outside and leaned against a lamp post.

Bob had seen the whole thing and came over to ask John what had transpired.

"He wanted something for his cough but I couldn't find the cough syrup. I substituted Ex-Lax and told him to take it all at once," John explained.

"Ex-Lax won't cure a cough" Bob shouted angrily.

"Sure it will" John said, pointing at the man leaning on the lamp post. "Look at him. He's afraid to cough."!!