When I'm deeper in my cups than usual and find myself visited by the maudlin spirits who serve as the closest things to guardian angels old drunks can hope for, I'll find myself pining for the youth I like to imagine I could have had but had slipped through my fingers.
Drink enough and it's not only your vision that grows blurry but your memories. The particulars become less distinct, their shapes more amorphous and you find yourself molding them into something unrecognizable. You cast your mind back and pretend that the only reason that you were isolated is that, in a act of foolishness or cowardice, you chose it for yourself. Had you the courage your ears would have been filled with the laughter of others rather than the oppressive silence of some library. If you hadn't, of your own volition, sequestered yourself from the world your nostrils would have been filled with the scent of perfume rather than the dust of old books no one cared about except for yourself.
Every step you take across the floor of your dim little cell as you continue your experiment in time travel is no different than that of a sleep-walker, one foot in the world of waking reality and the other pacing through the land of dreams. You smile one moment imagining all of the good things you could have experienced, only to find yourself on the verge of tears the next believing that you've missed out on them. Turn this way as you look at the world through your half-closed eyes, and you can see the silhouette a loving wife by your side or a baby cradled in your arms. Turn that way and their vague shapes dissolve, returning to the darkness you fashioned them from. It's a terrible experience, isn't it? Devil to your left, your wrist firmly clutched in its claws, pulling you toward the Hell you had walked down into with your eyes wide open, the angel on your right pulling you toward memories of things that could have been but never were. Both Life and Death hold their unique terrors, but more terrible still is belonging to both and, thus, neither. Neither Day and Night have rejected you and the thing about the liminal space between the two is that one who's trapped there has no idea whether he's subject to Dusk or Dawn, whether it's Noon that's awaiting him or Midnight.
You stumble about like a ghoul; laughing, weeping, raging in turns. Until, eventually, you find yourself in front of a mirror. You study the grotesque thing you see before you and the spell at long last breaks. The ugly thing before you didn't secrete himself away from the world of his own accord, he had been exiled from it. He chose the silence of the library because the only laughter he would have heard had he ventured outside of it would've been derisive. He became acquainted with the scent of rotting old tomes because his repulsiveness precluded the possibility of a woman allowing him to approach close enough to smell even the faintest hint of her perfume.
There's a reason why undead things despise mirrors: just a bit of glass and metal can dispel the delusion of abominations, things cursed by Nature, that they truly have any semblance of life or, for that matter, ever did. The magic of the mirror murders every dream of what could have been or what could ever be, it kills the Dawn and allows Dusk to deepen into Night.
Mourning is reserved for the things that once were and now are no longer, that which has passed from the World of the Living down to the Land of the Dead. We only weep for someone or something lost if had existed to have been lost in the first place.
There's no reason to cry for what has never been, no sense in holding a funeral for the things from whom the closest thing to either a cradle or marital bed they would ever sleep upon is the grave.