An e-mail exchange with a customer:
Me: Have you tried a, b and c?
Them: Yeah, it still doesn't work
Me: Hmm, odd. Let's try d and e. But a, b and c worked for me.
Them: No, still nothing?
Me: This is really weird. Could you provide me with [lots of information].
Them: [Information]
Me: Hmm, and it definitely doesn't work if you do a, b and c?
Them: Hi Dan, it now works if I do a, b and c.
Except that took a whole morning and lots mroe e-mails