A customer asked for help diagnosing a problem they were experiencing on Windows XP:
My customer reports that on their machines, they do not get the warning balloon that appears when Caps Lock is set while you are typing into a password field. I searched for relevant KB articles but couldn't find anything related to that. Can you help?
Time for the psychic powers.
My psychic powers tell me that the customer disabled all balloon tips.
The customer liaison replied
You are right. Thanks for the help.
This is a not uncommon situation with some customers. They change a setting, and then later report that they're having some problem caused by that setting. They don't bother going to a freshly-installed machine to see whether the problem occurs there as well, in order to isolate whether the problem is related to their customizations or not. They just assume that their customizations couldn't possibly be the cause of the problem, and they are so convinced of this that they don't even mention "Oh, we customized this setting" when they ask for help.
By the way, the setting to disable all balloon tips in the entire system is a rogue feature. At the time that balloons were originally being developed (and the rules surrounding them being refined based on research and feedback), one developer was impatient with the progress toward making the balloons less annoying, and he just went in and added a rogue feature to disable them with a sledgehammer. And now that people know about it, the rogue feature has become a support burden.