Have you ever had a feud with your ex before? The anger is so palpable, you can't even bear to see the person for even one more second? Can't stand his/her quirks that used to be what actually caught your eyes in the first place? Have you tried to solve any misunderstandings that may exist? Give a contrite apology for something you may have done wrongly? And finally when you realize you're in the wrong and when he/she is already gone, you start searching for her frantically and begging her to come back to you.
You thought of a million ways to placate her, hoping she will come back to you. You did all you can but she just scowl at you, asking you to be gone. Finally you sat down forlornly, thinking of 'I should have...', 'I should have...'. You cry is imperceptible, you try to keep it as quietly as possible, hoping no one will see your tears. You spend an inordinate time thinking of what should you do now etc. etc. anything that can make her enthralled to you once again.
Your best friend ask you to get up and not do any preposterous things like beg her for another chance cause she will just end up riding you and take you for advantage again when your best friend clearly have no idea what the misunderstandings of arguments may be about. Perhaps even you and your ex don't even know.
Love can be so simple. Yet so cryptic. Communication is the most important factor. One must understand the other before leading to any major arguments that may be due to each parties' insufficient understanding of each other. Without communication, a 'couple' will just be 2 living things walking together thinking that they understand each other.