It takes less energy to set the thermostat at a reasonable temperature, 78 degrees or above, and leave it there, than it does to turn the AC up or off during the day when no one is home. It takes more energy to try to cool down a warm house than it does to just let it run during the day.
Our AC is set at 78 during the hot months, even when it's 105 outside, and we are comfortable inside. Our electric bill is very reasonable compared to others who keep their thermostats lower.
If I am visiting someone who sets their thermostat lower, I am extremely uncomfortable; it's just too cold. (And I am generally more warm-natured than others, so I don't know how they can stand the colder temperatures.)
Conference rooms in hotels are notoriously too cold. They set the thermostats at 68 degrees, everyone is turning blue and needs sweaters to keep warm. I have never been at a conference in a hotel where the temperature was comfortable.