“Dìdi,” (a term of endearment meaning younger brother) is what Chungsing Wang (Joan Chen) calls her son (Izaac Wang), but this Taiwanese teenager in Freemont, Calif., prefers his American name, Chris. This is one of the many conflicts Chris has with his mom, who embarrasses him in front of his friends or nags him about studying — especially since her friends’ kids are overachieving....