There are twelve types of customers, each with different levels of tipping and patience.

Type	How to unlock
Average tips and impatient	Female student.
Average tips and patient	Woman with brown skirt, man with grey pants, prom queen (little pink dress), male student.
Bad tips and impatient	Punk boy and Goth girl.
Bad tips and very patient	Grandma and grandpa.
Good tippers and impatient	Businesswoman, businessman, bride (pink dress with tiara).