For those of you who have wondered about the many ways you can start up your Mac, here's a list of the Mac startup keyboard shortcuts you can invoke to access handy macOS features, which are only available at boot time.
Most of the time, your Mac just works—until it refuses to start up properly due to an unforeseen system error, a misbehaving app, a broken system component, and whatnot. Beyond system errors, different people have different needs when it comes to starting up their computers.
For example, you could be a pro user who dual boots between macOS and Windows on a daily basis. Others might be wondering about booting a Mac from a disk other than their designated startup disk. Or perhaps you're looking to isolate the cause of a software issue in the macOS Safe Mode or boot straight into Recovery OS as the last option?