Experiences, in one way or another and by varying degrees of intensity, differ from one person to another. If not already, it should be considered a scientific law of the universe. Life experiences - human experiences - cannot be duplicated because of various factors such as differences in environment, upbringing, previous experiences, emotional condition, physical condition, personal values and beliefs, perspective, and so on. What I mean is, one person's experience at a concert will vary from their best friend's experience. To say their experiences were exactly the same would be as preposterous, and ludicrous, as saying that two objects can occupy the same space. So saying to someone who has recently lost a good friend of their's, or a family member, that you "completely understand" would be to be exactly that - preposterous. What turns out to be ironic is that a person's declaration of complete understanding is a black-and-white indicator of their lack thereof. As similar as any two experiences may be, Billy's loss is not equivalent to Justine's loss. Let's take, for example, a case where I lose a loved one. A person tells me they "completely understand what I'm going through". Though he or she too may have experienced a loss of a loved one, that person's loss was not the same person as the one that I lost. Our relationships with them differed, they died at different moments in our lives, they died of different causes. Need I continue? Any loss ever experienced cannot ever attain equality with my loss. To assume otherwise, besides being incredibly stupid, would be borderline offensive as well (especially in the case of losing a loved one), because it suggests that the person in my life who is now dead was not a unique individual. So my message to the world is this - to lack understanding, is to understand. Sympathy doesn't need to be accompanied by understanding to be a comfort. In fact, it's almost more comforting to sympathize without understanding. The only thing that is left for the sympathizer to do is to carry the burden of pain, offer up your experience as well as any other useful advice you can extract from it, and hopefully it will provide ease into the victim's situation.