The discussion centers on identifying gases that are easier to compress than air. It highlights that compounds which are vapors at room temperature but have boiling points close to that temperature, such as 1,2-butadiene and butane, are easier to compress. These gases can transition to liquid form under moderate pressure, making them more compressible than air. Additionally, some chlorofluorocarbons (Freons) are noted for their compressibility. Overall, the conversation emphasizes the behavior of gases under varying temperature and pressure conditions.