Hard Riddle: Who spends the day at the window, goes to the table for meals and hides at night?
From the point of views of all the people around the globe all a fly does all day is to figure out how to get in or get out from a closed window, to fly around and to go to tables with the aim of finding food for itself while people eat on that table.
At nights flies hides away and only come out when there is a light. Even though we mostly interact with the flies at summer, most people hate them or are revolted by them thinking they can be on anything all they and they mighty carry diseases.
The answer of this riddle is a fly.