There have been a number of "favorite/recommended restaurants in Bangkok" threads here over the years. The sub-forums have changed ~ 3 times so I'm honestly not sure where those threads are now, but a search might reveal many great recommendations?
Generally, when asking you might mention a preference? Thai food (Royal, Chinese, Issan), Japanese? Asian? Indian? Middle Eastern? Muslim? Western? And what type of restaurant, hotel, buffet, food-court/coupon, aircon, open-air, street sit-down, cart. Location also helps.
IMO, open-air Thai restaurants offer the best in food quality, atmosphere and value.