I was going to say this, but I never run across it on TV. 
I have a few. “The Heat” with Sandra Bullock and Melissa McCarthy is one I just watched again a few days ago.
The only movie that I can think of that fits (plays often and likely to come up while channel surfing) is National Lampoon’s Christmas Vacation.
Big Trouble in Little China
The Full Monty
The Shawshank Redemption
Gone With the Wind.
Key Largo.
any Fred Astaire/Ginger Rogers movie.
National Velvet.
Galaxy Quest.
A little known but mesmerizing 1937 film ‘Night Must Fall’ - Rosalind Russell becomes attracted to a serial killer in a quiet English village.
When I’m in a hotel channel surfing I’m a sucker for monster and alien movies from the 1950s like Earth vs The Flying Saucers, Them!, The Black Scorpion, This Island Earth and of course The Thing from Another World .
I rarely watch a movie more than once. But here’s my list
Groundhog Day
Air Force One
Galaxy Quest
My Cousin Vinny
Rear Window and Stalag 17* are such near-perfect movies that I have trouble resisting the temptation to watch at least parts of them when they’re on TV, even though I’ve seen them each at least a dozen times.
*“Ach, soooo.”
Just remembered: The Day the Earth Stood Still (the original).
I’ll never understand why Patricia Neal didn’t just grab the kid (Bud from Father Knows Best) and fly away with Klaatu.
I caught The Fugitive while channel surfing a few nights ago.
Phew! I had forgotten how fast-paced it is. Harrison Ford and Tommy Lee Jones both did a fantastic job playing the hunted and the hunter.
I watched the tail end of Pulp Fiction too. It never grows old.
All of the Connery/Moore Bond films, definitely Live and Let Die
Ferris Bueller
WarGames
The Karate Kid
Stripes (at least the first half)
The Original Star Wars trilogy and the prequels.
I don’t often run across much prior to the 1980s in channel flipping mode. For Star Trek films, it depends on which one and my mood at the time.
The Godfather
Rain Man
Tootsie
The Incredible Shrinking Man
The Princess Bride.
How can I be the first person to say The Fifth Element?
Galaxy Quest
Multiplicity
Joe Vs. The Volcano
I like to see guys I think are funny doing their thing, somehow it just plays better than standup a second or third time.
Raising Arizona.
I lack the ability to deny myself watching this movie spiral into its final amazing action/comedy sequence. If it’s on and I know about it, I watches.
Plus, this scene is a genius scene:
Hehehe, the current embedding bug an my ineptness caused that to not work. Here it is:
Both Unwatchable Edited for TV.
Your Glaz-Ball providers Don’t Vitty Well, Lit’l Sister!
Yojimbo paired with A Fistful of Dollars if I have a whole evening to kill.
Blues Brothers by itself, ditto.
The Train Burt Lancaster, Nazis, and trains. How can I resist.
A Knight’s Tale just for the sheer absurdity.
Young Frankenstein ditto.
Galaxy Quest double ditto.
A Funny Thing Happened on my way to the Forum I’m sensing a trend here.