Discussion topic: What are some perceptions that you've had or still have in Star Wars for things that weren't or still aren't revealed in official canon? Have any of these perceptions since panned out differently or did they work out the way you imagined years/decades ago?

As a kid growing up watching and re-watching Star Wars over and over again since the 80s, there are many ideas and images that sprang in my mind over what the expanded universe was like, based on what I heard and saw in the Original Trilogy. Here are a few (most of these are ideas I had from childhood).

The Clone Wars
I thought that it was the Jedi who were cloned, not Stormtroopers. I thought that there was a big series of wars where the Jedi Knights were the front line soldiers, not rare officers, and that their number had become so depleted against the enemy (Sith soldiers) that the Jedi were forced to bolster their numbers with clones. I thought that Ben Kenobi was one such clone, and that his clone number was OB-1. Idea of a Sith army was also quickly debunked with the Rule of Two.

Jedi garb
I was expecting Jedi to have a completely different uniform from what they have now, and I still think that they should have. Until 1999, I always thought that Obiwan Kenobi's clothes were simply regular civilian clothes. After all, Owen Lars wears the same style of clothing, and he's not a Jedi. Even Luke's costume in A New Hope is a lighter version of this (he's just not wearing a skivvy and hooded cloak). I was honestly expecting the standard Jedi dress to be more similar to what Luke wore in Return of the Jedi (which is actually more similar to Yoda's costume). Why would Obi-Wan Kenobi continue wearing Jedi robes during his time in exile on a populated planet while hiding from the Empire who were explicitly hunting down Jedi Knights?? I could understand Yoda not bothering since he's living in an uninhabited world... it's not as if a swamp rat is going to report a sighting to the Empire's security hotline. Obi-Wan enters freakin' Mos Eisley wearing that get up while it's crawling with Stormtroopers. And how smelly would that costume be? It's not as if Obi-Wan had time to pack his wardrobe... eewww... No wonder he was a hermit...

Bothans
As a kid, I misheard "Bothans" as "boffins" and I thought that the Rebel spies who sacrificed themselves to bring the Rebels intelligence about the Second Death Star were a rag tag mixed group of Rebel techies... kinda like what we ended up getting in Rogue One. Turns out they're an alien race. Still, I'd like to see a film in the vein of Rogue One which looks at the plight of these Bothans. And we know that the Empire was better prepared this time, allowing the Bothans to steal false intelligence as bait for the Rebel Fleet.

Anakin Skywalker
I viewed Vader as a fallen angel, and hence Anakin would be angelic; Anakin was the prime example of the Jedi... he was their brightest and their best. Instead we had this whining, greedy, jealous, impatient and angry Anakin Skywalker. But while it's not I expected as a child, as an adult I can see that the Anakin we got made more sense. Because a perfect Jedi wouldn't be corrupted by the Dark Side. We don't see the likes of Yoda or Mace Windu being seduced by the Dark Side because they are too confident and assured in the Light Side. They walk so brightly in the light that the shadow of the dark cannot touch them. Anakin would be like this too if Lucas had portrayed him as I'd imagined him. But thankfully he didn't, and it makes more sense. The Anakin we got was insecure. He walked in the light but never far from the darkness... and at times he would tip into the dark (e.g. slaughtering Tuskens, executing Dooku). While Anakin was still a generally good man, he was a flawed man. And it would be these flaws that would ultimately lead to his downfall. A flawless character on the other hand just wouldn't be believable as a corrupted hero.
"Learn the Dark Side of the Force."
"Okay. It's never tempted me before, but sure. Why not."
This would be stupid. Lucas' version worked out well because Anakin had already tasted the Dark Side before. He's been tempted before and he's given into that temptation before. Anakin was susceptible to becoming morally conflicted. The Emperor saw this and exploited it (so did Luke, but it was for Anakin's own good and motivated by love). The Anakin that I imagined as a child and his transformation to becoming Darth Vader was more similar to Bayformers Optimus Prime... all altruistic one moment, then angry rage-driven vengeance machine the next.

Obi-Wan vs Vader
I thought that Vader would end up falling into a vat of acid, and that his ghastly appearance was a result of those sustained injuries. Nope. Turns out it was lava. Oh, and it turns out that Revenge of the Sith is arguably one of the more realistic portrayals of how a person would die in lava. It's slow and painful, not quick like in many other films - e.g. Gollum's fall into Mount Doom. What happened to Gollum and the One Ring should have been the other way around... the Ring should have sunk down pretty quickly while Gollum would be more likely to float and slowly burn.
For a detailed scientific explanation as to why, see this video: Why Death by Lava is Much Worse Than in the Movies