A humorous joke with irony?

1. A lady went to buy shoes. She tried on a pair of shoes and thought it was good, so she bought it. But it broke after wearing it for a few days. She went to ask the shoe store owner how the shoes were broken. Shoe store owner said, "Our shoes are all made of rubber." The lady said, "Then why don't you use plastic?" Shoe store owner said, "Our plastic shoes can't be worn after one day." The lady said, "Our shoes are all made of rubber." Shoe store owner said, "Then why don't you use plastic?" The lady said, "Our plastic shoes can't be used the next day after being worn for one day." 2. A man goes to buy shoes. He tried on a pair of shoes and was very satisfied, so he bought them. However, after he wore it for a few days, his shoes were broken, so he went to ask his boss how the shoes were broken. The boss said the shoes were made of rubber. He said, then why don't you use plastic? The boss says these shoes are made of rubber, but our plastic shoes can't be worn for one day and the next.