Sometimes life is like a Rube Goldberg device: a complex, convoluted, ridiculous series of ropes, pullies, levers, and rolling balls—which have to run in a very specific sequence in order for it to work. As you watch a real Rube Goldberg device, especially if you're participating in its creation, you might hold your breath at certain points: ooh, will it work? Will the ball roll down the track with enough force to bump the candle? Will that axle spin fast enough to hit the next item in the sequence?
Sometimes you experience your life in a similar way. While it's hard to watch it from above (you can only look back, not forward), every minute, day, week, month, you are adding to the Rube Goldberg device that is your life. Every little shift, opportunity, setback, or discovery comes to you because that's where it falls in your sequence. And to arrive there, you had to come through every ridiculous thing that happened before.
Of course, this metaphor has its limits. You have conscious choice, free will, and your choices affect the construction of your particular Rube Goldberg device and the experience of your life. But with so much you can't control (weather, flight delays, what kind of day your boss is having), imagining life through this lens can be very useful.