In the tabletop, spears are simple, versatile piercing weapons; the piercing equivalent of a quarterstaff. You hold it in one hand, you do 1d6 damage, with two, 1d8. Using a spear with a shield is a classic historical and fantasy aesthetic; yet I just looted a spear in game and I must use it in two hands and I can't use it with a shield. Why is this the case?