If you’ve ever been slightly annoyed about having to go fetch that torn-off corner of paper that you wrote your cryptic home wi-fi passphrase key on for a guest, then Microsoft has reason numero uno for you to upgrade to Windows 10: Wi-Fi Sense. In a nutshell, this feature – if you choose to allow it – essentially shares your wi-fi passphrase with your friends, as determined by your contacts in Outlook, Skype and/or Facebook. In a loosey-goosey sort of way, Wi-Fi Sense is fairly secure, though I don’t recommend it for the most paranoid among us.