Some post-WWII Western films began to question the ideals and style of the traditional Western. Elements include a darker, more cynical tone, with focus on the lawlessness of the time period, favoring realism over romanticism. Anti-heroes are still common, but with stronger roles for women and more-sympathetic portrayal of Native Americans and Mexicans. Regarding power and authority, these depictions favor critical views of big business, the American government, masculine figures (including the military and their policies), and a turn to greater historical authenticity. (consider Spaghetti Western as a separate category)
This is a particularly hard list. These are the scenes in cinema that moved you, made you cry, made you laugh, felt good or felt bad or just made you think. Either way, these are the movies scenes that will always stick with you for the rest of your life.