Pill at regular times??

So I'm on the pill and I take it every day "at about the same time". But sometimes I take it around 9 In the morning. Other times around noon. I try to be punctual but I don't really understand why exactly it has to be around the same time. I forgot my pill one day and I googled it and if I took it later I should be fine too. So is there a reason why it has to be so punctual or is it just so you wouldn't forget it or something? What do you think?