• For every one you see, there are a hundred you don't.
• There are a LOT of them.
• Ants exchange food by regurgitation (eww), and unhappy customers tend to spread their unhappiness. Call it viral anti-marketing, if you wish.

The solution? As soon as you see the first one, you have identified both a problem and a weakness, a symptom and a cause, and it is considerably less expensive to fix both right away rather than wait for things get worse.

Then again...

User issues are not like ants

• Hiring an 'exterminator' rarely works, nor does 'pesticide'.
• User issues are people problems.
• You can often solve the real problem simply by being nice and considerate.
• The problem was probably caused by you not being nice and considerate.
• User issues are hints about how, perhaps, your company should be evolving.
• If you don't have user issues, you aren't trying hard enough.