Just come back running.

Ahh those pesky customers/clients/end-users. What would we do without them (other than lead a life of sanity and bliss)?
The really scary ones are starting to come out of the woodwork here. We're not talking about the masses of people who just don't have a clue, can't find the 'on' button, don't know what the right-click is. Those hoards are my jam and peanut-butter. Solving their trivial woes and watching the light shine on their heads when they get something new fills me with a sort of magical laying-on-of-hands healer joy. Nor am I talking about the really squeaky ones, the pet customers. You know, the ones who have adopted you because you're the "only one who can help me". They have that supernatural ability to break any electronic device/software they come near, in ways you've never seen before - and with frequency that's just plain alarming. Somehow this also gives them an aura of pushiness. The things just break and they have no idea that they have no control over their energy field, and so they get uppity. These are the 10% of the customers that take up 90% of your time. I'm not talking about those either. Those I keep close to me, gather them around like leaves on a freezing castaway night. They keep me safe and secure when the bosses start to wonder how much work I'm actually doing.

Kiddie stuff, amateur night compared to the really scary customers. The ones I'm afraid of are the ones I don't expect. They lurk in the woods, keeping their eyeshine deftly away from my spotlight until I've passed them over, then pounce on me with bloody precision. Those are the ones that shake me to my core, get me thinking what a lovely career choice ditch-digging must be.

Example One: The Guests.
Boss Person - "Hey 'drink, we've got some people using facility-x here about two months from now, they need something taken care of up there before they arrive."
Largedrink -"No problem. They want something simple. I'll do my best to remember to get up there by then."
Forward by Boss Person from Guest Wrangler: "Do we need to have the guests give Mr. Largedrink a reminder? If facility-x isn't ready for them in two months we'll be in breach of contract with them."
So we have a five-minute fix that needs to be done in two weeks, and because I was quip enough imply that I could forget to do it someone is throwing breach of contract caltrops at my feet already? Slowing me down so the predators don't have to break a sweat before they eat me alive.
My fault I suppose, but you get the picture.

Example 2: The Lifer.
Around here we have a lot of lifers; customers who stake their claim on some old piece of technology. They hang on it and worship its black monotilthy goodness while the rest of us make fire and tools to fend for ourselves. No big deal. I'm all for it, technology forces people to change and not always in a way that makes their lives easier. If it's working, more power to ya. Our example Lifer is perhaps the kingmost of all the lifers I've met. He has said in nearly as many words "I'm going to keep technology-x until the day I retire. I want the organization to buy me a closet full of them so when one breaks I can just take the next one off the shelf and use it." Again, no problem, whatever. The only important items to note for this example are that A) Lifer needs technology-x and B) he does not have a closet full of them.
Here's a surprise: his favorite piece of technology-x broke. He brings it over, we look at it. Yep sure is dead. The good news is that he has a backup (he's learned that his Neanderthal tendencies have consequences and has planned accordingly). Not his primary choice of backup, but something workable for a while. Which is good because technology-x is so old we don't have any more of it around -kind of surprising where I work really. Broke technology-x goes off to the hardware department where they agree it's broken and unfixable. They proceed to scrape his personal belongings off it so he can move it to his backup.
Days go by, I get an email from Lifer:
"Been starting to worry - it's been an awfully long time for someone of my stature to be without his primary monolith, especially at this point in our cycle. My backup is doing okay (barely), but it's not something I can count only for heavy duty use. Should I have already sent the broken unfixable technology-x to the mothership if I expect to have it working before the crunch hits?"
Okay so I guess this one again is my fault. I had no idea how urgent his need to have the unfixable technology-x fixed, since it never came up in conversation. He wanted it evaluated, and fixed if possible, but never indicated how desperate his need was.

Having been in this world as long as I have, I can cope with these kinds of instantaneous unreasonable expectation turnaround menaces. Duck, weave, play dead.
The Guests: "Hey tell them not to worry, I'll have it all taken care of in time."
The Lifer: "Oh my goodness, I had no idea how urgent your needs were. My fault, I'm sorry. I'll get right on it an do everything I can to get it resolved as soon as possible."
Meanwhile I'm sharpening my pungi-sticks and mixing up my dung-and-clay facepaint. It's only Tuesday (yes as in O-n-l-y T-u-e-s-d-a-y (another inside joke)). Completely-out-there customers are getting restless, starting to climb down into the feeding grounds. Around here they're a tricky lot. They've been at their game along time. Unlike the natural world around here the old ones who are the strongest and most dangerous. They've gone almost senile in their instincts. They don't know when to strike. At any moment a seemingly placid customer will lash out like an injured lion. And me the lowly customer service dweeb; part doctor, part game warden. Save the ones you can. Keep a hefty stash of tranquilizer darts for the rest.
Any of you in the support/customer service industry know what I'm talking about. Wrangling customers is like herding ferrets. None of them do what you want. They're squirmy and hard to handle. Not to mention no matter how hard you try they all still smell like ferrets.
-'drink