You know it is time to pull the plug on a relationship when you've done everything conceivable to make your partner happy, but they fail to recognize your efforts and refuse to do their fair share. You've done everything imaginable to make the relationship work, but he or she continues to cheat, be lazy, take you for granted, or give you the cold shoulder. It's at this point you no longer feel guilty about walking away. In fact, doing so makes you feel liberated because it means you can finally pursue a relationship with someone who will invest the time and energy you do. A relationship that weighs you down -- one that leaves you feeling more dead than alive at the end of the day -- is no relationship at all. Rather, it is more like an albatross over your head that is inhibiting your growth. A good partner enhances our lives with traits that we may lack or that complement our own -- whether it's a great sense of humor, a flair for adventure, or a love of the a...