What to do when things go wrong with Git

Kate Hudson's Flight Rules for Git borrows from NASA's Flight Rules, which are:

... the hard-earned body of knowledge recorded in manuals that list, step-by-step, what to do if X occurs, and why. Essentially, they are extremely detailed, scenario-specific standard operating procedures.

The result is a recipe-style collection of Git tips & tricks to get you out of a jam. A few examples:

• When I try to push, I get an error message
• I committed to master instead of a new branch
• I made several commits on a single branch that should be on different branches
• I need to combine commits

The document is still a work-in-progress, so please get involved and add to the compendium!