1. Teach your mum the internet
As she endeavours to scribble down your instructions parrot-fashion on a notepad your patience is already strained. Your final breaking point will be somewhere between her asking if web addresses need to be written “all in one word” and calling the internet “the website”.
2. Take out point-of-sale insurance
After an hour and a half of form-filling you're left paying half a month's salary to insure your treasured gadget. Read the small print, however, and you find that all likely causes of damage – dropping, submerging, sitting on it a bit – are defined as “Acts of God” and not covered.
3. Click “Reply All” by accident
There's no feeling on Earth quite like that sickly rush of blood to the head caused by firing off a quick “Steve's a complete tool” missive to a colleague, only to see said tool's name appear in “Sent items”. Bonus points if Steve is your boss.
4. Go near a dodgy plug socket
You're master of the atom. You're lord of the land. But all it takes to unsettle this faith is one steely blue lick from a poorly wired socket. Once you've recovered, you'll have to re-route all 19 home cinema appliances into the multi-plug in the other corner of the room. That one's never let you down. That one wouldn't hurt you…
5. Fail to delete your internet browser history
Mostly a helpful feature that quickly navigates you to your most-viewed sites; occasionally a relationship-ending tattle-tale that informs your loved one of your smut habit. Remember: your browser history never forgets (unless you tell it to).
6. Open an email from a bank
“Barclays has an important message regarding my account? But I don't bank with Barclays,” you wonder. Maybe Barclays owns the bank you're with, or it's been hacked and your money's been transferred there for safety. Spam emails are either Viagra-related or involve Ugandan princes and this has neither, so it must be important… Oh. Nope, it's just a pop-up virus.
7. Stream HD content on a limited broadband plan
Otherwise known as “starting something you can't afford to finish”. Yes, Sky Go is a good service, but if your monthly broadband allowance is in the single-GB figures you can't afford to get too engrossed in Game of Thrones.
8. Exit a taxi without checking you've still got your phone
Waking up without your fifth appendage is a horrifying moment of realisation akin to remembering your partner's birthday a day late. You can call the cab rank to see if anyone honest actually works there if you want, but you already know the answer.
9. Stay logged in to Facebook
Friends: they'll cheer you when you're down, help you when you're in need, and ruin your life given two minutes alone with your Facebook account. In that short time the skilled Facebook molester can change your profile pic to a shot of Joey Essex and announce that you're undergoing corrective penis surgery.
10. “Reflashing the BiOS ” on a malfunctioning Windows laptop
According to our Lifestyle Editor Duncan Bell, this is unwise.