Ham is one of the best-remembered characters in the movie, despite having relatively little screen time. It helps that he says some of the most meme-tastic lines in the film (see Memetic Mutation and Signature Scene).
Squints is very popular amongst the fans, too, even though he features in only one scene.
Family-Unfriendly Aesop: Forcibly, nonconsensually kissing a girl is an important, cheeky rite of passage. It's said that they were "banned from the pool forever that day", but this is a sidenote, so the example is still valid. She's even said to have been impressed by it and married him in the epilogue.
Smalls' mother telling him to get into trouble during the summer (not too much, but some) becomes not so funny after the actor who played Smalls got arrested 20 years later.
It's hard to imagine Squints getting off with just being banned from the pool for life over his stunt. Sexual harassment and matters of consent have become Serious Business even for children. Today he could likely expect serious ramifications. Since the movie took place in the height of the Mad Men era when sexual harassment was as American as apple pie, he probably would've just gotten slapped back then.
Harsher in Hindsight / Hilarious in Hindsight: Depending on how you look at it, at the end of the film, Bertram is revealed as getting into the 60s and no one saw him again. Bertram's actor, Grant Gelt's final acting credit was for a made-for-tv movie called "The Sixties".
The standoff between the Sandlot kids and their rival team.
Ham: You play ball like a girl!
The chase scene with Benny and the Beast.
Benny: Sandlot! Sandlot! Sandlot!
The how you build some s'mores scene.
Ham: You're killing me Smalls!
Sequelitis: The second movie is not really liked due to its Recycled Script. Subverted with the third movie, since it is better received, but not as much as the first one.
Special Effect Failure: The cutaway shots of fireworks during the Fourth of July game are stretched horizontally (the fireworks appear oblong), meaning non-anamorphic stock footage was spliced into the film.
The animatronics used in many scenes for The Beast don't hold up particularly well. Though in a bit of Fridge Brilliance that may make them work even work better considering his mythic status among the kids.
Vindicated by History: When the film was originally released, it received mixed reviews and made a modest box office profit. Nowadays, it's considered to be both a classic family film and one of the greatest baseball movies of all-time. 25 years after its release, 20 Major League Baseball teams had a "Sandlot" night where they hosted the cast members, handed out merchandise such as t-shirts or bobbleheads, and celebrated the film's lasting legacy.