This year in the Marvel Cinematic Universe (MCU), Guardians of the Galaxy Vol. 2 set a new standard for post-credits scenes, with not one, not two, but five post-credit scenes. Needless to say, the post-credits scenes in Spider-Man: Homecoming had a lot to live up to. For it's first post-credits scenes, the newest installment to the MCU went a more traditional route, setting up a new potential villain for a sequel, but the second post-credits scene in Spider-Man: Homecoming is unlike anything Marvel has ever done before, and it's all thanks to Captain America. Spoilers ahead!
Instead of setting up future movies (like the two Captain America: Civil War post-credits scenes) or setting up the next Avengers film (à la Doctor Strange), Spider-Man: Homecoming's second post-credits scene is basically one big punch line. The scene is quite simple: a message from Captain America, who stands in front of a bright white background, speaking directly to the audience. "Patience," Cap begins. The scene is a short wink to the audience members who have stayed in their seats through all the credits, with Cap teasing viewers that sometimes one's patience doesn't pay off. The video, done in the style of the educational videos shown at Peter Parker's high school (as glimpsed in the trailers), doesn't reveal any new information about the MCU, or even hint at a collaboration between Cap and Spider-Man. So, in fact, any audience members hoping to get real, juicy information from post-credits scenes will be very disappointed. As the Captain says, sometimes patience doesn't get you what you hoped for.
If nothing else, the post-credits scene is a nice ending to Cap's string of cameos in Homecoming, all done via-educational videos. There's one about fitness shown in PE class, one about following the rules shown in detention, and even one about puberty. (That last one, unfortunately, is cut off before the audience can even hope to hear Captain America utter the words "sex" or "menstruation.") The running joke is bound to be a fan favorite, especially considering Captain America's post-Civil War status as, essentially, a criminal hiding from the U.S. government. It's a nice callback to the Captain America of The First Avenger, the one created as a piece of U.S. propaganda, government property used for the benefit of society.
Captain America's appearance in the second post-credits scene in Spider-Man: Homecoming shouldn't come as much of a surprise. Actor Chris Evans has been very vocal about his desire to cameo in Homecoming, telling MTV International that he'd love to be in a Spider-Man movie. "Those are going to be fantastic, and I think Tom [Holland]'s just a great actor, so that might be a fun one to pop up into," Evans said. Well, what the Captain wants, the Captain gets.