Why does the monthly accounting closing process in the U.S. always get stuck on invoices and credit card reconciliation?

Anyone in accounting and finance knows that the truly annoying part of month-end closing isn't clicking a button to generate reports, but the small gaps that no one ever fills. Supplier invoices arrive late, a credit card receipt is missing, or an expense is casually dumped into the wrong account—only to be discovered at the end of the month, forcing you to chase people down everywhere. I am now…