I think it is some kind of privilege for left-handed people in CiV world. You work hard for many turn and then rest in the city until your leader need work again which after most of landmass is settled and improvement is built, You gain either eternal residence in city or retirement. You also gain privilege as International Law stated that "Left-handed man shall not being attack with club, sword, pike, musket, rifle and any firearm or melee weapon. If military regiment marching through left-handed people that belong to enemy country. Left-handed shall be granted citizenship of soldier's country"
I am left-handed too