Nhai kĩ no lâu, cày sâu tốt lúa ("Chewing carefully [makes one] feel full longer, ploughing deep is good for the rice") = Careful execution brings better results than hasty actions.
Chán cơm thèm phở ("Inappetence of rice, desire of noodle") = A men gets bored of his wife and find another girl.