Not that there is anything wrong with that. But, sometimes you really like a movie, think it’s good to great, but there’s no real plot or story. I was thinking about this especially when watching The Whale. I remarked in its thread that though I enjoyed more on retrospect, there really wasn’t much of a story. Also:

The Station Agent
Infinitely Polar Bear (though it deals with a common and real subject, but no real story)

Hard to capture the idea (I am supposing) of your thread title. Sometimes a movie feels like an 'easy watch' for me, like it just ambles and is fun to spend time with even if there's no destination. Totally American Graffiti. Rocky feels like that for me too; you don't need a prize fight to enjoy spending 2 hours with Balboa.
Gerry by Gus Van Sant is pretty close to a movie 'about nothing' in that you can summarize the plot in 3 words - hikers get lost - but it's a masterpiece anyway.

Lost in Translation

Diner
My Dinner With Andre

Cheech and Chong's Still Smokin

All movies go somewhere. But I think I understand. My favorite movies are often labeled “meandering”.

Goodfellas and Waking Life are two that come to mind. Boogie Nights. Repo Man.

Before Sunrise

Goodfellas and Boogie Nights have full story arcs. They are most definitely about "something ".

This may not fit the bill but My Neighbor Totoro does have a plot but it's a pretty simple one with low stakes. But still a fantastic movie. Similar for something like Kiki's Delivery Service.

Dazed and Confused, and its "spiritual followup," Everybody Wants Some!!

Lotta Richard Linklater in this thread. Add Slacker and Boyhood to the list.

I kinda feel The Banshees of Inisherin falls into this. After watching it, it felt like a long Irish Seinfeld episode to me.

The Neverending Story and The Night House are two good movies that are essentially about nothing.

^ The Neverending Story, not have story? Did you actually see the movie?

^ Think it’s a joke about the Nothing.

Ah.

The Big Lebowski , Coffee and Cigarettes and Dazed and Confused

Clerks.

There’s a story IN there but a lot of Once Upon a Time in…Hollywood spends a lot of time meandering through 1960s Hollywood. There’s a good chunk of “A day in the life…” being shown.

Dazed and Confused

I think it just took forever to get to "the point or grievance" but it was definitely about something.

Pulp Fiction.

When I hear the phrase "about something" I assume it's referring to themes or ideas. Those are different than plot and story. Most of the films mentioned in this thread are definitely "about something".

All movies are about something. Seinfeld was always about something. I was going for what it meant to me.

Take your pick from any of Warhol's films from the 60s ('good' being subjective, of course ).

Being a Jean Rollin fan, I'll recommend The Iron Rose.