Yes, Yellowstone is crowded, and there are a lot of foreign tourists who are less familiar with our wildlife, rules and language than they perhaps should be. However, it's still a marvelous place. What you want to spend your time seeing will depend on your interests, or you could focus on different things different days - spend a day at Old Faithful area, walk the boardwalks & try to catch an eruption of some of the other geysers there; spend another day in Lamar or Hayden Valley watching wildlife; take picnics for lunch and find a spot (there are a lot of picnic areas). Make sure to visit the visitor centers - each "area" (where lodging, food, etc. are offered) has one, and each one focuses on different aspects of Yellowstone. If you want to see the quieter side of Yellowstone, visit Lake area and/or Grant Village, and be sure to walk around West Thumb. The parking lot is a pain but the thermal area is IMO the prettiest in the park.
For when you want to buy an inexpensive meal in the park (relatively speaking :) ), check out the deli in Lake Hotel, the cafeterias in Lake Lodge or Canyon, and the larger "General Stores"often have burgers, hot dogs, and ice cream (and the ice cream is especially good!) Dinner in Lake Hotel & Old Faithful Inn will require advance reservations, and are expensive, but the food is quite good (trust me, it didn't used to be, some 40+ years ago - I know from serving it back then. :) )
