As ice cream shops come and go throughout the metropolitan area, successful ones often need to find an angle to differentiate themselves. That may mean unique flavors, a specific style, or an inventive presentation. At the north end of downtown Phoenix, a small store known as Fatty Daddy’s (sometimes written with the initials “OG” in front of its name on social media) has created its own niche by offering ice cream side-by-side with espresso, boba, bubble waffles, macarons, and cookies in a sort of Asian-American-European celebration of frozen desserts.