If this is hard for them to understand, the confused look when you reveal a change was a net removal of lines/statements must be amusing!

> Because the issue was reported with a vague description of how to recreate it

This is something my current management fully understands, but I wish we could get through to our clients. Short of being actively rude about bad requests I've run out of ideas over the years. Luckily these days we are big enough that I usually have a bit of a shield (provided first line support people and BAs who I trust) between me and direct client contact.

I'm quick to put tickets on hold as "needs more information", and been around long enough that I've developed the confidence to respond to "this is urgent, there is an SLA" with "and that service level agreement covers a minimum level of reporting from you before even an urgent matter can be progressed" or more facetiously "then it is urgent that you furnish me with the information requested", but while they accept it each time they never learn to give better details up-front next time - we still get reports of "an error" or something "not working" or, even worse, the open-ended question "is there a problem with...?".

Obviously this can't be applied to truly urgent issues, but they are usually massive problems that we are already aware of and working on before the client contacts us because, for instance, we've had an alert that something is down (sometimes we tell the client about an issue and resolution ETA before they notice, which they seem pleasantly surprised by and thankful of).