I used to have this stupid rule. Okay, I say 'rule' but more of a loose idea about people. Cancer's my star sign and sometimes I play up to it too literally, hiding myself and my emotions in my little shell. I've also had my fair share of hurt and a little heartbreak so I would devise my circle of trust and no-one else could enter that 'safe place.' And sure it definitely was safe but limited.
I'm a firm believer in that you shouldn't put all of your eggs in one basket and that applies to people too. By your twenties you'll have manifested a whole network of contacts. From relationships to colleagues and friendships to acquaintances, your phone will be bursting with people to brunch with, open up to and call at 2am if need be.
Shutting people off will protect you in the short term but will also mean you miss out on so many emotions in life in the long term. Trust that those you let in are in it for good intentions and if not, they're an experience and will add character to your life. It'll also strengthen your inner being by how you handle those situations too.
I'm still learning. Whilst I can be 100% honest with my friends, I haven't mastered how to switch off ice queen mode with relationships. I'll deny for months and months and then years down the line a lightbulb will go off and it's usually too late. Don't be like me on that one. If not just for your own benefit, but for theirs more importantly. It's not nice to not know, or to think someone doesn't care when in fact they mean the world to you. That reservation can break hearts and that ain't nice. Always tell the truth, it's scary as hell, but at least it's a weight off of you, and they'll know where they stand.
People serve all kinds of purposes in your life. Let certain people in to let you laugh, let others in to be your 'call anytime' person, others to do the stupid immature things you can't do with anyone else and others to be whatever you need them to be. Whilst I advocate being 100% whole on your own, being able to stand alone and all that jazz, you can't be that pillar of strength or resilient to anything if you barricade yourself off from the world. Because as John A.Stedd once famously said "a ship in harbour is safe - but that is not what ships are built for." Be a ship but don't be static. Let the waves of life hit you, pass you by and sail through with grace and battle the storms people bring your way the best way you can. But above all, let people in. Let them change you, let them shape your life and make it all kinds of wonderful. Be okay alone but always remember no man is an island, he needs his people too.