Have you ever reached for a drink of water, then realized, half-way through your first sip, it was Sprite? I like Sprite, but that first sip of a similar-looking, but very different liquid is a shock.
That's how Elixir can feel if you're coming from Ruby. The syntax looks similar, but Elixir is different from the first sip. For a smooth transition, you need to (a) learn some functional programming patterns and (b) unlearn some Object-Orientated habits.
A core design pattern of Elixir is the focus on data transformations: you'll see it in libraries like Ecto.Changeset, Ecto.Multi, Plug.Conn and built-ins like Enum. Let's dive in.