Do I have a good or bad taste in films?

Good/bad taste is a matter of opinion not fact. So as long as you enjoy the films you've got good taste. From your list in my opinion you've got good taste (Forest Gump, Slumdog Millionaire, The Damned United, etc...) and bad taste (The Godfather trilogy, Tropic Thunder, Adulthood, etc...). But my opinion is different from everyone elses. Some may think all the films are good taste, some may think bad taste, some may agree with my opinion, some may have the exact opposite opinion. You can have films like Strange Things Happen At Sundown (worst film ever) or Spongebob Squarepants (for kids) but as long as you enjoy them you have good taste in films.