assign_quirk_effect

assign_quirk_effect = {
	if = {
		limit = {
			exists = var:my_quirk
			var:my_quirk = flag:fallback
		}
		remove_variable = my_quirk #to give character's that were assigned the fallback a chance for better things
	}
	if = {
		limit = {
			NOT = { exists = var:my_quirk }
		}
		hidden_effect = {
			random_list = {
				1 = {
					trigger = {
						OR = {
							has_trait = shy
							has_trait = pensive
						}
					}
					set_variable = {
						name = my_quirk
						value = flag:shy
					}
				}
				1 = {
					trigger = { has_trait = arrogant }
					set_variable = {
						name = my_quirk
						value = flag:arrogant
					}
				}
				1 = {
					trigger = { has_trait = impatient }
					set_variable = {
						name = my_quirk
						value = flag:impatient
					}
				}
				1 = {
					trigger = { has_trait = lustful }
					set_variable = {
						name = my_quirk
						value = flag:lustful
					}
				}
				1 = {
					trigger = { has_trait = chaste }
					set_variable = {
						name = my_quirk
						value = flag:chaste
					}
				}
				1 = {
					trigger = { has_trait = temperate }
					set_variable = {
						name = my_quirk
						value = flag:temperate
					}
				}
				1 = {
					trigger = { has_trait = gluttonous }
					set_variable = {
						name = my_quirk
						value = flag:gluttonous
					}
				}
				1 = {
					trigger = { has_trait = greedy }
					set_variable = {
						name = my_quirk
						value = flag:greedy
					}
				}
				1 = {
					trigger = {
						OR = {
							has_trait = diligent
							has_trait = bossy
							has_trait = curious
						}
					}
					set_variable = {
						name = my_quirk
						value = flag:diligent
					}
				}
				1 = {
					trigger = { has_trait = lazy }
					set_variable = {
						name = my_quirk
						value = flag:lazy
					}
				}
				1 = {
					trigger = { has_trait = wrathful }
					set_variable = {
						name = my_quirk
						value = flag:wrathful
					}
				}
				1 = {
					trigger = {
						OR = {
							has_trait = calm
							has_trait = pensive
						}
					}
					set_variable = {
						name = my_quirk
						value = flag:calm
					}
				}
				1 = {
					trigger = { has_trait = impatient }
					set_variable = {
						name = my_quirk
						value = flag:impatient
					}

As written in game/common/scripted_effects/00_personal_details_effects.txt.