I've never actually seen a bad Western. I keep "Blazing Saddles" and "Little Big Man" on rotation for viewing about once a year.
“Blazing Saddles” and “Little Big Man” are two of my favorites, along with “Cat Ballou”. Yes, I have a strange sense of humor.
Although any western with Tom Selleck, Sam Elliot, or written by Louis L’amour are winners.
And Lonesome Dove.