Like catching characters speech patterns tells you a lot about their personality (which often does not make it into the translation)
This is very true. Thing is, when I was playing Japanese video games for example, (even before studying Japanese), I was like “wait, he didn’t say that, this is a terrible translation” so many times. Though when you learn about the language you realize, it simply doesn’t make sense if you translate it to English word by word. For example, character may say “Hayai!” and translation would be like “Great! You are fast!”, so that doesn’t actually fit but you can’t simply translate it as “Fast!”, that wouldn’t be natural English. In some cases translators even add jokes themselves, sure that’s nice but sometimes jokes are so out of character or have other issues.
In the end yeah, these little things are pretty fun and I’m a person who likes learning stuff, that’s the only reason I study Japanese actually.