When it wrecked us: Season five, episode 15 ("Bullets Over Bel-Air")
Why it wrecked us: While withdrawing money from an ATM, Will and Carlton are suddenly held up by a gun-toting robber. The assailant pulls the trigger, and Will gets shot when he shields Carlton from the bullet. A guilt-ridden Carlton becomes angry when the attacker isn't found and blames his naiveté on Uncle Phil who made him believe in law and order. Carlton secretly purchases a firearm for self-defence, but when Will finds out, he tearfully begs Carlton to hand over the gun.