While I believe director Greta Gerwig's later film Little Women is much better, Lady Bird is a good-enough coming-of-age movie. It's nothing special, but it can be funny at times and the actors deliver some decent performances.
Psycho has had a huge impact on not only horror movies, but movies in general. With its incredible cinematography, compelling story and iconic twists, it's no wonder why this is regarded as director Alfred Hitchcock's greatest film.
Poltergeist has a lot of memorably scary sequences that are tame enough to have a PG rating yet still manage to be as gruesome as they can possibly get away with. It's not perfect, but it is a really good horror movie.
The best way to tell that you're watching a film by Guillermo del Toro is if it has incredible makeup and practical effects yet horrible CGI. Hellboy is pretty much the same way, with a couple of interesting characters but not much else in the story or action department.