Some gamers insist on playing only games that they are familiar with. I’m not sure I understand that mentality — I’m a bit of an omnivore with respect to gaming. Finding out how a game works, what kind of stories are told, and how the rules support that — that’s part of the fun for me. And the kind of game you get when playing, say, Blades in the Dark, is totally different than when you’re playing Dungeons & Dragons. Why would you limit your experiences like that?
When I’m playing a Ranger, Druid or Wizard, I sometimes get to pick an animal as familiar. In my experience, the familiar doesn’t really play a large role in the adventure, other than to scout ahead (if it’s a bird) or to pick something from a narrow space (if it’s something like a rat). As a result, I don’t pay it a lot of attention.