As business owners, when it comes to cutting costs, we often look for big ticket problems because they are both appalling and glaringly expensive. The reality I have found, however, is that little mistakes are more frequently the cause of the biggest losses. They are often repetitive in nature and add up quickly. A big problem may cost you $1,000, so you'll be quick to quash it, but small snafus of only $100 each happen left and right with no alarm bells being sounded.
Teach your employees not to hide their errors, but rather to be willing to share them with teammates. Have management shower these problem logs with positive, rather than negative attention, so that the team sees them as a way to learn and grow, never a means of persecution and punishment.