All data regarding Player-induced damage is reset after logging out.
For example, if a Player angers an Spider(in light), Enderman, Wolf, or Iron Golem, upon re-logging, said mobs would no longer be hostile.
This also applies to lit TNT and projectiles when, for example, if the Player logs off while an arrow is in mid-flight, upon re-logging, when the arrow hits one of the said neutral mobs, the mobs would not be aggro-ed since the game forgot who shot the projectile.