When you turn the air conditioner to a colder temperature, you are actually turning the A/C down.
The temperature scale on an air conditioner typically indicates the desired temperature setting, and turning it "down" means you are decreasing the set temperature. This results in the air conditioner running for a longer duration and cooling the room more.
While it may seem counterintuitive because we often associate "up" with increasing values, in the context of air conditioning, turning the temperature "up" would mean increasing the set temperature, resulting in less cooling and a warmer environment.