For the longest time, I associated space opera with one thing: big space battles. I may well have gotten that impression before I ever heard the term “space opera.” My parents let me watch the Star Wars movies when I was around kindergarten age (I have a distinct memory of finding the bit with Luke’s hand terrifying, thanks so much, Mom and Dad!). Even later, when I started reading science fiction and fantasy in middle school, book cover illustrations told me that you couldn’t have a space opera without big space battles in them somewhere.
Time passed. I read more space operas: Debra Doyle & James D. MacDonald’s Mage Wars series, Jack Campbell’s Lost Fleet series, Lois McMaster Bujold’s Vorkosigan Saga, Simon R. Green’s Deathstalker Saga, Alistair Reynolds’ Revelation Space, Peter F. Hamilton’s Night’s Dawn series, David Weber’s Honor Harrington series, Orson Scott Card’s Ender’s Game, James S. A. Corey’s Leviathan Wakes, Ann Leckie’s Imperial Radch trilogy… This isn’t an attempt at a comprehensive or “best” list, and indeed, some famous examples are missing by virtue of the fact that I have never read them (notably Frank Herbert’s Dune and Vernor Vinge’s A Fire Upon the Deep).
Big space battles continued to be a feature, yes. But I noticed that some space operas had a difference of emphasis when it came to those battles. In some of them the big space battles were foregrounded, just as future tank warfare is foregrounded in David Drake’s The Tank Lords—if you’re not interested in hardcore tank action, you might as well not read that book. (I was very much interested in hardcore tank action.) In others, the big space battles were not the focus—or anyway, not the only focus.