Stress
You can't be serious. There's just no way tinkering with a messed-up computer causes stress—hey, you live for opportunities to tear apart computers. You can't imagine anything better than somebody actually paying you to do it. If you got to do it all day long, it would be better than winning the lottery (well, maybe).
That sounds great in theory. However, suppose your day's assignments aren't exactly linear; that is, they aren't scheduled in a logical sequence. Instead, you're buried in the bowels of a client's two-generation-old PC, trying to figure out why it keeps shutting itself down.
Now you get a text from your boss, telling you to get to a ladies' clothing store halfway across town. They're right in the middle of a sale, and their computer-based POS system just gave up the ghost. If you don't get it fixed ASAP, they'll lose a ton of money when their customers walk out in a snit. Stress level going up yet?
Now add in two more scheduled clients, plus an emergency call from a business that can't generate its payroll checks because its computer system just got fried by lightning. Meanwhile, you just guzzled down a giant iced coffee that's probably got enough caffeine for six people. You're not sure if it calms you down or hypes you up—but it'll help you cope with your steadily mounting stress levels.
Oh, and your boss just texted you again. That can't be good. He's wondering what's taking you so long.