alt Hacker NewsLife is full of moments like that. For example on your way to work that same morning, had you left your house 30 seconds later than you did, someone might have had to wait at an intersection longer than they otherwise would have, causing them to narrowly miss being in an accident further down the road instead of being hit. Butterfly effect and all that. You can’t predict the future.
I don't worry too much about the butterfly effect because it goes both ways. Sure one stoplight here makes a guy die, but another stoplight over there saves a guys life.
But in this case, when it's a clear "either I put off changing my oil and washing my car, or this 250 lb senior citizen with gout tries going on a hike", it's a lot more clear.