What makes A New Hope's two signature scenes so iconic?

When talking to someone about Star Wars (either the series in general or specifically A New Hope), two scenes from A New Hope almost invariably get mentioned: the opening scene with the two spaceships, and the cantina/bar scene.  The other day, a thought occurred to me: just what is it about these scenes that makes them stand out in the viewer's mind?  With that question in mind, I rewatched those two scenes and made the following observations:

The Opening Chase:

• It makes for a memorable opening
• There is the opening crawl, then we see a spaceship flying past the screen, with lasers firing back and forth, all of which has been seen before.  Then, however, we are shown who is pursuing that spaceship, by having the underside of the pursuing Star Destroyer slowly fill the screen until we think it just can't get any bigger.  Even when viewed on TV or a computer screen this shot is still quite impressive, but when seen on a big screen it is truly spectacular (especially if it is the first time an audience has seen something like this).  
• It drives home the David and Goliath aspect of the rebels vs. the empire
• Just looking at the relative size of the two ships drives home the odds the rebels have to overcome and how powerful the Empire is.
  
• It started a trend for the opening scenes of the other films in the trilogy, and other works
• The Empire Strikes Back and Return of the Jedi both used a shot of a Star Destroyer for their opening scenes; similarly, Timothy Zahn's Thrawn Trilogy had each book open with a scene taking place on the bridge of a Star Destroyer.
  

  

  The Empire Strikes Back

  

  

  Return Of The Jedi

• It draws the audience in
• Having an action-filled introduction, with both ship-to-ship combat and an infantry-based firefight, makes for a compelling opening sequence, and keeps the audience interested in the rest of the film, even during the more slow-paced sequences that follow on the surface of Tatooine.

The Bar Scene:

• It's thematically important
• Star Wars: The Legacy Revealed describes the scene as the "Crossing the Threshold" part of the hero's journey.  The door to Luke's past way of life has been shut; when he enters the Cantina, it's his first step into the wider universe.  In addition, the bar scene introduces the characters Han and Chewbacca (RIP Peter Mayhew), and also shows the lightsaber in action for the first time.
• It's a classic example of a "big reveal" 
• Up until now, all lifeforms seen in the film have been either humans, animals, or aliens who were always seen wrapped in robes.  Now, however, we not only see alien lifeforms, but we see such a sheer variety of vastly different species that it's almost overwhelming.  In addition, the alien lifeforms look truly "alien", rather than just humans with pieces of rubber glued to their ears or foreheads.
  
  
  
• It's both utterly alien and highly familiar at the same time 
• For all the ways that the bar is alien, there is still something oddly familiar about it; the bar is highly reminiscent of anything from an old west saloon to a pirate's tavern to a Prohibition-era speakeasy to the inn that the farmers in The Seven Samurai stay in when they try to hire samurai.
  

  

  Back To The Future Part III

  

  The Seven Samurai

  

  

  The Magnificent Seven

  

  

  High And Low

• It creates the feeling for the audience that there's a larger universe out there, beyond just the protagonists of the film
• Looking at the other people and aliens in the bar, I often got the feeling that if the film had followed them around instead of Luke, Obi-Wan, Han, and Chewie, it would make for a film just as interesting (well, OK, almost as interesting).