Air conditioning units can be too powerful! Not too powerful in the sense that you’re going to start a blizzard in your own home, but in that it can be oversized, which causes it to short cycle, turn off and on again, as well as waste power and not properly cool your home.
When an air conditioner is too powerful, it doesn’t have to run as long to achieve the desired temperature. This results in the unit shutting off sooner, which means it has to turn back on again more frequently. This causes the unit to work harder, which leads to more wear and tear, and can also cause the unit to break down more quickly.