First Rated R film you've ever watched ?

No idea, as my dad started letting me watch R-rated movies when I was 6. Probably a Steven Seagal movie like Our for Justice or Hard to Kill.

Scream. I think I was 12

Lethal Weapon 2, I think.

My parents didn't keep me from watching R-rated films in my childhood. I want to say The Matrix was probably my first R-rated movie, but it could very well be Goodfellas as my dad watched that whenever it was on.

Fists of Fury (incorrectly titled as The Chinese Connection because those titles were switched) - 

That is also probably where I first said "endings matter" tbh - because that has a great one ......... and I saw it in a theater with my whole extended family who were basically the only ones in the whole revival theater showing it

I have no clue how exactly that actually happened  ....... back then the Pacinoyes Respected International Clan Kollective (or "Prick" for short) was aggressively breeding.......... my cousins were there too running up the aisles, throwing stuff..........screaming their heads off .........like they were "children" or some shit..........it was pretty awesome / traumatic.....

Not debating that but also not giving up on my battle.

I'm sure it's an action movie..... like Arnold's Commando, JCVD's Kickboxer, or First Blood.... something like that. There's also proof me and my brothers watched tons of horrors at like 6-7y/o... Leprechaun, Chucky, Hills Have Eyes, etc. But the first movie where I was aware it was "R" - explicitly told I shouldn't be watching parts of it..... Dressed to Kill

I mean, I was watching them on TV since early childhood so I really have no idea... must've been some action flick with JCVD or something. The one I consciously remember is probably Once Upon a Time in America which I watched in my parents' room while pretending to be asleep (I'm not exactly sure but I must've been like 4 or something).

I have no idea of what constitutes R rated movies in America - some of the ones people listed in this thread look totally random.

I think I saw Rosemary 's baby when I was 11 or something, and that's probably R rated for you.
I avoided rewatching it for the following 40+ years btw.

The ratings really are random. General rules that are often broken arbitrarily:

One f-bomb is (usually) allowed, more than three is absolutely, 100% not safe for kids, we can't poison them like that! Two is on a border that nobody wants to bother with, so there is little data to go on.

Lots and lots of violence is okay, but there shouldn't be blood and DEFINITELY no guts. Thus, The Ballad of Buster Scruggs, which shows a bit of a messy red splotch in the back of character's head after getting shot: slap an R rating on that baby. Any James Bond movie in which he kills dozens of people for escapist fun: perfectly acceptable. On-screen decapitations in The Hobbit are acceptable, as there is no blood.

Absolutely no frontal male nudity, unless seen from a very long distance. Female frontal nudity can be allowed if the MPAA isn't turned on by it, but usually it gets slapped with R. Rear nudity is almost always allowed.

That said, there are exceptions to all of these. Princess Mononoke is a particularly funny example to me: It got a PG-13 rating despite having some strong violence and gore in there. In fact, the word "gore" is used in the MPAA's own description of why it got PG-13! Any other movie that gets labeled with gore is automatic R. It's completely random what they will do next, it's really quite funny.

From what I recall of the doc This Film Is Not Yet Rated, I think you're allowed a couple f-bombs in a PG-13 movie as long as they don't have an explicit sexual connotation. So if a character says something like "I fucked your wife," then it's an automatic R.

And full-frontal male nudity is allowed in R-rated movies as long as the penis is flaccid. If it's erect, then you get an NC-17.