Your friend can't blame you for not answering if you say your phone is dead. Just ignore their texts of "Where are you?" and "I thought we were supposed to meet?" and "Are we still on? hello!?!?!" Respond way way way way later with a classic, "Oh my gosh, my phone died!!!!!! So sorry! Can we raincheck???"
Warning: you actually have to keep up the charade that your phone is dead. That means no Facebook, Instagram, or Twitter presence for the entire "dead" time.
This excuse is gold! Schedule a hang out weeks in advance. Say the only day you're free is August 1st. Then the night of July 31st, pull the "this month has been really rough, rent's due tomorrow and I'm so broke $$$$$, I don't think I can go out :/" What is your friend going to do? Get mad at you for living the struggle? No! Now your night is free for you and Netflix to get nasty.
The car trouble excuse is perfect for a last minute bail. You know the kind: thirty minutes before you are supposed to meet up you feel that it would actually be way more rewarding for you to stay at home and count how many cheeto puffs come in a standard bag. Give them a quick little text with anything car related and you are golden. Something as simple as, "My car is overheating, I need to stay here and wait for Triple A. GRRRRR" Be careful that you never use any excuse with which they could help. That means no flat tires, dead batteries, or towed cars.
The most important part of backing out of plans is making your friend(s) feel like you really, really wanted to hang. Everyone lies about being sick so just saying you're sick isn't good enough. If you tell someone that you are sick, you better be snapchatting them sickly sad faces every 15 minutes so they know how important they are to you. Backing out of plans takes work, people.
Ain't nobody mad when you are going through something emotional! All you have to do is say, "I'm so sorry, I can't make it tonight. I have to deal with something." They will ask if everything is okay to which you say, "I don't know yet, I hope so." Leave it at that! The less they know, the less they can fact check.
Tell them you got held up at work. It's run of the mill but the way to make this work is to immediately post "I Miss You" by Blink 182 on their Facebook wall. Internet gestures are the new Edible Arrangements.
Okay maybe not that many hours, but everybody understands sleep deprivation. Shoot them a quick text saying you haven't gotten "like any sleep this week" and you would be "such a snooze tonight anyways". Follow it up with some night time emojis and you're in cancellation station.
We're all adults and the want to "just stay in" is not limited to you. Everyone knows what it's like to want to ball hard on some Law & Order SVU at home. Getting yourself into social guru mode takes a lot of energy and no one will blame you for not feelin' it. Unless you back out of your grandmother's funeral. In which case, you are garbage.