This is the most hilarious deleted scene ever and it is from Back To The Future which makes it even more funnier and mildly disturbing. The scene features a awkward conversation between Marty (Michael J. Fox) and Doc Brown (Christopher Lloyd) about how weird it is for Marty that he has to hit on his mom, who has a crush on him. Doc doesn’t seem like it’s too much of a big deal, and amusingly encourages Marty to take a “few liberties” with her, and then gives Marty a creepy wink that is a little disturning. Marty replies to that with, “I can’t believe I’m going to feel up my own mother,” and then expresses his concern for how this is the kind of thing that could screw him up in the future, using an example that it could end up turning him gay. That line is raising some eyebrows as being homophobic and offensive.
The most funniest part was when Doc misinterprets a lot of the “modern” terms that Marty uses. When Marty says “hitting on her,” Doc says, “No one said anything about hitting her!” As for the gay line, Marty says “What if I go back to the future and end up being gay?” This sets up the following punchline for Doc: “Why shouldn’t you be happy!?”