This is one of the variations of the proverb "For Want of a Nail" that has numerous variations over several centuries. This reminds us that seemingly unimportant acts or omissions can have grave and unforeseen consequences.
Don't belittle it even if it's a small thing. As Laozi said earlier "Do the difficult things while they are easy and do the great things while they are small. A journey of a thousand miles must begin with a single step," you have to take care of small things carefully to do big things well.
#trivial #omission #fault