If people start with "Hi, I have a problem" and don't state what the problem is I just respond with "drop me the details and I'll have a quick think" and get back to my work. Even if they respond immediately to that it might take me ten or fifteen minutes to get look at their message again - that is their time wasted, not mine.
Some problems require a more urgent response so I'll accept a walk-up or a shout for those, and some problems are best illustrated by showing them than describing them, I just have to trust people to know what they are and what is less urgent. And of course a message will come in at a time when I am eminently interruptible, in which case people get an immediate response anyway.
I find it works except for people who insist on not following the process, but they soon learn I'm far more helpful if they don't irritate me!