Contribution to core and contrib can be quick and easy

Contributing to Drupal core and contrib has never been easier.

We no longer have to wait +1h for core tests to run, we no longer use patches (and why this is good), creating MRs and running CI tests is within a few clicks... when we use the right tools and the right workflow.

Why was contribution difficult before? What has changed? What if I want to keep doing what I was doing? How do I "go with the flow"?

Tools and workflow that would make your contribution easier.