I swear some nerds have severe Alzheimers disease and forget that Batman's parents were murdered in front of him as a child, his second sidekick was beaten to death with a crowbar and then blown up, and Batgirl was shot in the spine and permanently paralyzed. The guy doesn't live in a happy, fun, quippy world filled with sunshine and high-fives.
Unless of course your only exposure to the character has been Batman '66 or Brave and the Bold.
-Mother abandoned him and his father when he was a toddler.
-Blinded as a boy, struggles to cope with the heightening of his remaining senses.
-Father beaten to death following the biggest night of his career.
-Girlfriend murdered by one of his arch-enemies.
-Another girlfriend hung herself.
-Another girlfriend murdered by the same arch-enemy.
-But not before she got addicted to drugs, started doing porn, and sold his secret identity to another arch-enemy, who used the information to ruin his life.
-Wife driven insane by another arch-enemy.
-Has been driven insane himself on more than one occasion.
-Secret identity exposed to the public on more than one occasion.
-No longer has a secret identity, because he's given up on the pretense.
-Actually killed one of his arch-enemies in a fit of rage.
-Tried to kill a baby because "the devil made him do it."
-Law practice is constantly on the verge of going under.
-Closest friend in the world and law partner gets diagnosed with cancer.
-Struggles every day with real depression.
STILL manages to smile, be quippy and crack jokes.
Batman's personal tragedies are a flimsy crutch for explaining why the character can't be depicted as anything other than dark, morose and brooding.