I've spent a bit of time using Linux as someone who considers themselves a regular grass toucher so use this as a guide to actually enjoying your computer again and dropping Windows.
Something that is both a blessing and a curse with Linux is the nature of how it is developed is that the fact you're using Linux is generally quite abstracted away from what you day to day.
Linux is a base (technically the kernel) of all these varieties (formally known as Distributions or Distros) of operating systems.