The world is a messy place, and despite our best efforts to control that mess, things will go wrong and you will not be able it any more than you are able to block an eight-foot tall wave from knocking you to the ground.
Where I see this play out is in people’s finances.
People borrow money to the absolute limit of their ability to repay. The next week their father ends up in the hospital and they need to help with the cost of the stay.
People spend down to their last dollar and hope that they can make it to payday. Then their car won’t start.
People give every dollar a job in their budget, but forget that things happen. And when “things” do happen, they say “how could I have known?”.
Nassib Teleb in his book Fooled by Randomness (Amazon) points out that while trying to figure out if something bad will happen today is impossible, on the whole in life, you can know that things will be going wrong and that really there is a pattern to randomness (the normal distribution or bell curve). The book is fascinating for investing nerds and insurance buffs, but is probably not for everyone. The point is: SOMETHING will go wrong. You don’t know when you don’t know why, you don’t know how, but it will go wrong, so build it into your plans.
Please, take a lesson from Nassib and build in some slack / flexibility / buffer into your life / schedule / budget. Build up an emergency fund for when you discover that your car tires need to be replaced, or you want to help a friend who can’t pay their rent because they’ve been laid off, or you need to pay the IRS more than your anticipated.
As for me, my furnace just went out. It was a small repair, but I should anticipate that it will completely fail someday in the future and start saving accordingly.
Q1: Where are you denying that you need space in your systems? (I don’t like the word slack, because it seems to suggest that people are being lazy rather than being wise by acknowledging reality.) Is it your time? Your money? Your relationships? Your job responsibilities?
Q2: Do you feel guilty about building in that space? One problem of pursuing efficiency in life is that we can forget that we’re humans and not machines, and so we don’t make the allowances for the things that really help us thrive (rest, play, relationships, reflection).