You might think you know someone inside out, but you probably have some serious blind spots.

It’s easy to get stuck in the shallow end of a relationship, never really diving into the deep stuff. However, getting to know someone on a deep level is a whole other kettle of fish. Here’s a list of things that separate your casual acquaintances from the people you really, truly know.
1. You’ve seen them seriously lose their temper.

We all like to think we’re cool as cucumbers, but everyone’s got a breaking point. Seeing someone when they’ve completely lost it — whether it’s a meltdown over a cancelled flight or a full-on shouting match with a neighbour — shows you a side of them that’s raw and unfiltered. It’s not always pretty, but it’s real.
2. You’ve had a blazing row and come out the other side.

Arguments happen, but it’s how you handle them that really shows what you’re made of. If you’ve had a proper barney with someone and managed to work through it, that’s when you start to see their true colours. Do they fight fair? Can they admit when they’re wrong? How do they handle making up? These moments can make or break a relationship.
3. You’ve been skint together.

Money troubles can bring out the worst in people. If you’ve ever been so skint you’re counting pennies for a pint, and you’ve got through it together, that’s when you really see what someone’s made of. Are they generous even when they’ve got nowt? Do they turn into a right miser? It’s all telling stuff.
4. You’ve seen their gob-smacking dance moves.

Everyone’s got their guilty pleasure tunes, and seeing someone absolutely lose themselves to their favourite song is priceless. Whether they’re dad-dancing at a wedding or having a kitchen disco in their pants, seeing someone let loose and not give a monkey’s what they look like shows a level of comfort that only comes with really knowing someone.
5. You’ve helped them move house.

Moving day is stressful as hell. If you’ve helped someone lug their life from one place to another, you’ve seen them at their most frazzled. How do they handle the stress? Are they organised or a complete mess? Do they appreciate your help or take it for granted? It’s a real test of character.
6. You’ve seen them ill as a dog.

When someone’s poorly, all pretences go out the window. If you’ve seen them snotty-nosed, voice gone, looking like death warmed up, you’ve seen them at their most vulnerable. How they handle being ill — whether they’re a right drama queen or stoically soldier on — tells you a lot about them.
7. You know their family drama.

Everyone’s got some family skeletons in the closet. If you’re privy to the ins and outs of their family dramas — the feuds, the black sheep, the embarrassing relatives — you’re in the inner circle. It means they trust you enough to let you into that personal part of their life.
8. You’ve seen them fail at something important.

Failure’s a part of life, but it’s how people handle it that really shows their mettle. If you’ve been there for someone when they’ve royally cocked up something important — whether it’s bombing an interview or mucking up a relationship — you’ve seen a side of them that not everyone gets to see. How they pick themselves up (or don’t) says a lot.
9. You know their guilty pleasures.

Everyone’s got those things they love but are a bit embarrassed about. Maybe it’s trashy reality TV, cheesy pop music, or eating peanut butter straight from the jar. If you know someone’s guilty pleasures, it means they’re comfortable enough to let their guard down around you.
10. You’ve been on a long journey together.

There’s nothing like a long car journey or a backpacking trip to really get to know someone. How do they handle boredom? Do they get ratty when they’re tired? Can they go with the flow when things don’t go to plan? These situations can bring out sides of people you never knew existed.
11. You’ve seen them absolutely legless.

Now, I’m not advocating getting plastered, but there’s no denying that alcohol can lower inhibitions. If you’ve seen someone properly sloshed — singing karaoke badly, pouring their heart out, or dancing on tables — you’ve seen a side of them they might not show when sober.
12. You know what keeps them up at night.

Everyone’s got those 3am worries that plague them. If someone’s shared their deepest fears and anxieties with you — the stuff that really keeps them tossing and turning — it means they trust you on a whole other level. It’s not the surface-level stuff, but the deep, sometimes irrational fears that really show you who someone is.
13. You’ve seen them smash it out of the park.

Just as important as seeing someone fail is seeing them succeed. If you’ve been there for their biggest triumphs — whether it’s nailing a presentation, running a marathon, or finally asking out their crush — you get to see them at their most confident and jubilant. How they handle success can be just as revealing as how they handle failure.
14. You know their weird food habits.

Food can be weirdly personal. If you know someone’s strange eating quirks — like how they always eat the crust of their pizza first, or how they can’t stand foods touching on their plate — it means you’ve shared enough meals to notice these little idiosyncrasies. It’s the little things that make someone uniquely them.
15. You’ve weathered a crisis together.

Nothing brings people together like a shared crisis. Whether it’s a natural disaster, a personal tragedy, or even just a really stressful work project, going through tough times together shows you how someone handles pressure. Do they panic? Do they step up? Do they look out for other people, or only think of themselves?
16. You’ve seen their living space at its worst.

How someone keeps their home can tell you a lot about them. If you’ve seen their place when it’s an absolute tip — not the cleaned-up-for-visitors version, but the real, lived-in mess — it means they’re comfortable enough to let you see the not-so-perfect parts of their life.
17. You know their childhood stories.

The experiences that shape us in childhood often have a big impact on who we become as adults. If someone’s shared their childhood memories with you — the good, the bad, and the embarrassing — it means they’re letting you understand the roots of who they are.
18. You can sit in comfortable silence together.

This might seem a bit odd, but being able to sit in silence with someone without it feeling awkward is a sign of true comfort. If you can just be in each other’s presence without feeling the need to fill every moment with chat, it means you’re past the point of trying to impress each other and are just content in each other’s company.