There could be many reasons, but some have been:

Air Flow

Some apartments with fewer windows/ doors (on each wall) may need air conditioning because of the poor air flow.

The more built up the area, the less air flow through your apartment/property.

Having a corner property may mean you have ventilation on two or more sides,however a central position which backs onto another apartment may mean that the only breeze comes in through the front entrance.

Some shops and older local buildings have the same problem. If you are working in a south west facing office with no rear window, then you would need to pay to buy and install an air conditioning unit.

Some windows in commercial property may be non-opening, which means that unless you keep the door open there is no free flowing ventilation.

If there are opening windows, check to see if they can be locked when in the open position. Open windows let in dust and may be humidity.

There are some newly built shops that have large pane's for the window, with no window opening to allow are to circulate naturally.