"Most important of all I continue living up to my motto: "Dignity, always dignity.""
Don Lockwood says this to his fans after telling them the less-than-truthful story of his rise to stardom. He believes that one should always pursue dignity, no matter what. Since we the audience can see that his story doesn't line up with what actually happened, we realize that he doesn't actually live by his own motto. He has stretched the truth and his real autobiography is not dignified at all, having worked his way up through smoky saloons and the vaudeville circuit. The irony lies in the fact that while he says that his motto is about always maintaining dignity, he forfeits his dignity in his desire to be a star and have the "right story."
"For heaven's sake what's the big idea? Can't a girl get a word in edgewise?"
Lina comes off the premiere stage after Lockwood has cut her off from speaking multiple times, and she is displeased with having been silenced. With this line, we hear her voice for the very first time, and we begin to understand why Lockwood wouldn't let her talk; her voice is very nasal and unattractive. Here, she scolds Lockwood for doing all the talking and reveals just how rude and abrasive her personality is.
"People think we lead lives of glamour and romance but we're really lonely...terribly lonely."
Don says this to Kathy when they first meet, not as a statement of truth, but as a way to get her to feel sorry for him so that she will want to get closer with him. While his comment might contain some truth—namely, that fame has alienated Lockwood from the world of interpersonal relationships—he is also very much using it as a line to try and seduce Kathy.
"Make 'em laugh!"
Cosmo says this to Lockwood in order to cheer him up when he is down in the dumps about missing Kathy. Cosmo is an enduringly comic character, always making light of situations and trying to find the joy in life. If Lockwood's motto is "Dignity, always dignity," then Cosmo's is "Make 'em laugh!" Cosmo's impulse to show people a good time and make them laugh has never let him down and it serves him well in his career, as he is always able to turn a negative into a positive.
Don Lockwood: Call me a cab.
Cosmo Brown: Okay, you're a cab.
This is a light-hearted moment between the two old friends that shows their playful relationship. Cosmo is Lockwood's side-kick, but he is also his comic relief. This quote happens when throngs of excitable fans are all but attacking Lockwood on the street. Cosmo, the less-famous of the pair, watches with a bemused expression, and when Lockwood asks him to help, Cosmo cannot sympathize, but only offers this witty one-liner. Lockwood wants Cosmo to get a cab to pick him up, but Cosmo pretends to take Lockwood's request literally, shrugging slyly.
"What do they think I am, dumb or something? Why, I make more money than Calvin Coolidge! Put together!"
Lina loves to ask people if they think she is "dumb or something," throughout the film, a question that always strikes an awkward chord, as Lina does in fact seem quite dumb. Here, having heard that Kathy is dubbing her vocals, Lina is incensed and tries to blackmail the studio and uses her star power as leverage, bragging about how much money she brings in for the studio. She brags to Simpson that she makes more money than Calvin Coolidge (a former president), but then reveals her stupidity by implying that Calvin Coolidge is two separate people, a business rather than an individual. This quote is one of the funniest in the movie as it indirectly reveals how dim Lina really is.
"I can't quite visualize it. I'll have to see it on film first."
Simpson says this to Lockwood after Lockwood describes the "Broadway Melody" number that he envisions for The Dancing Cavalier. This line strikes an ironic tone with viewers, as we have just watched the entire number, an approximately 15 minute, lavishly staged and choreographed affair with hundreds of dancers, revolving sets, and a climactic narrative. The irony is that Simpson has not actually seen what the viewer of Singin' in the Rain has. While we have gotten to witness "Broadway Melody," all Simpson has heard is Lockwood's description of the number. After such a gigantic musical number, it is humorous to hear someone say, "I can't quite visualize it."
"You keep away from me! Just because you're a big movie star, wild parties, swimming pools, you expect every girl to fall in a dead faint at your feet. Well, don't you touch me!"
Kathy says this to Lockwood when he first jumps into her car when fleeing from crazed fans. She makes a point of telling him that she is unimpressed by his celebrity status and movie credentials. His hard-partying, glamorous life does not impress her (or so she says) and she scolds him for believing that his movie star clout means that she will automatically fall in love with him. On the contrary, Kathy wants Lockwood to know that she is not attracted to him in the least and she wants him to get away from her. This quote shows that Kathy is tough, down-to-earth, and not easily seduced by mere superficialities.
"Ladies and gentlemen, stop that girl, that girl running up the aisle. Stop her! That's the girl whose voice you heard and loved tonight. She's the real star of the picture. Kathy Selden!"
Lockwood says this after he, Cosmo, and Simpson pull open the curtain to reveal that Kathy was the one actually singing for Lina. Embarrassed and feeling betrayed by show business, Kathy tries to escape up the aisle in the theater, but Lockwood calls on the audience to block her way, and announces that she is the beautifully-voiced actor behind Lina's performance in The Dancing Cavalier. Here Lockwood finally gives Kathy the credit she deserves, recognizing her for her unsung talents as a performer and, by extension, communicating his love for her.
"She's so refined. I think I'll kill myself."
This is a humorous line, mostly because it demonstrates the delirium of the movie fan's admiration for the screen star. The audience member is certainly exaggerating, but just the fact that she expresses a desire to kill herself at the sight of Lina Lamont's refinement is grossly over-the-top and disproportionate. It's just a movie!
While it is unknown to the audience at this point in the film, this line takes on an even stronger irony later, because we learn that Lina is, in fact, anything but refined. The perception of her as a refined lady is completely misaligned with her off-putting and ugly personality.
