In the modern world, being passive aggressive is easier than ever before. In a few minutes, you can subtweet, throw shade with a tea-sipping Kermit meme, and finish off a bitchy Whatsapp message with a cheeky trio of see no, hear no, speak no evil monkeys.

But passive aggression – real, true passive aggression – is a lot more serious and a lot less obvious than a few bitchy statuses. It is technically defined as indirect hostility, negativity and resistance to demands. And it's much more complicated than the old cliché of a post-it note on your housemate’s unwashed dishes, as more often than not, it’s actually non-verbal.

So what, right? We’re all passive aggressive from time-to-time, and what’s the real harm of a dirty eye-roll in the direction of Janet from accounts? Well, according to psychologist Dr Elle Boag, a senior lecturer in Social Psychology at Birmingham City University, passive aggression can lead to the breakdown of relationships, social anxiety, and depression.

Here are six warning signs of passive aggressive behaviour, and how to deal with it in others and yourself.