These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
One-Scene Wonder: Cyd Charisse in the "Broadway Melody" sequence, without even a single word of dialogue.
Padding: The film is only about an hour and a half long, and quite a lot of that time is taken up by musical numbers that have almost nothing to do with the plot, like "Beautiful Girl" and especially "Broadway Melody". However, those numbers are so awesome that it's difficult to care.
Uncanny Valley: The frozen tableau of girls in the "Beautiful Girls" number is a little off-putting.
Values Dissonance: Don gives a completely false account of how he got into acting, mentioning having attended prestigious acting schools while he actually honed his acting skills as a street performer and in minor, lackluster roles. This would be an utterly baffling thing to do from the perspective of a modern viewer, who would be much more likely to relate to a classic ‘underdog’ story instead of that of a person who rode his privilege all the way into glory.
Vindicated by History: The film did disappointing box office and was generally snubbed by the Oscars, but is now seen as one of the great movie musicals of the 20th Century.