In the imperative, “shut the door” would be less polite but only marginally, but would not be considered rude if used descriptively as in, “He shut the door.” or if embedded as noted in the comment above by Silenus.

In the imperative, “shut the door” would be less polite but only marginally, but would not be considered rude if used descriptively as in, “He shut the door.” or if embedded as noted in the comment above by Silenus.