Aries: They doubt themselves. They need reassurance and validation from people they love, and if you give them this, they'll be your loudest, strongest, most enthusiastic cheerleaders. They'll always stand up and fight for you (even if they know you're in the wrong)... if you do the same for them. Don't take this for granted.
Taurus: They will put themselves first. Always. It's because they feel like no one else does, though; they always get taken for granted and ignored and they get so sick of it. They will break your heart with their selfishness, but they do love you. Believe them when they say it.
Gemini: They're lonely. Even surrounded by people, a Gemini can be so, so, lonely, because they long for emotional closeness and a deep mental connection. They lose interest in people so quickly because this connection isn't there with most people.
Cancer: They're mean and selfish. They guilt trip and play the blame game, because they don't want to face the truth about themselves. They act tough, talk shit, hang out with people they don't really care about, and they try to pretend that this is who they are. It's not. They're trying to protect themselves from the harsh, judgmental world by acting like they hate the best parts of it.
Leo: They blame themselves for everything. A Leo may act like a diva, throw a temper tantrum and accuse you of ruining their life, but inside, their heart is breaking because they failed themselves. Not only that, but they failed you, too. And they hate themselves for that. They have trouble forgiving others, but they have even more trouble forgiving themselves.
Virgo: They are not cold. They are actually sensitive and easily hurt, and they protect themselves by building a robotic, analytical exterior. They have such high standards for the people in their life because they're scared of getting hurt. Deep down, a Virgo just wants to throw away all their worries and inhibitions and be free.
Libra: They're incredibly loyal. Once a Libra decides they like you, they may stray, lose contact, hang out with other people, but they will never completely forget you. At some point, they will always come back to you. They value friendship and love more than anything; this is both their best quality and their biggest weakness. They give people so many chances, and as a result they are used and hurt so many times, because they never lose faith or become bitter.
Scorpio: They need someone to tell their thoughts to. Scorpios are secretive and mysterious creatures, but they can't stand having no one who really knows them. A Scorpio is selective about who they trust, but if they do trust you, you will be surprised about how open they are.
Sagittarius: They don't bounce back so easily. Sagittarians are not always happy-go-lucky and content. A Sagittarius is prone to feelings of inadequacy and anxiety, but they do their best to hide this from people. They are incredibly strong, but they still fight their personal battles like everyone else and can be very sensitive. They don't need to be coddled or helped through difficult times, they just need you to stand by them while they fight their demons.
Capricorn: They care the most, but have the worst time trying to show it. Their natural tendency is to hide their feelings and retreat from those they care for. They confuse people with their hot-and-cold behavior. They frustrate themselves, because they want to throw themselves into everything they do, but they can't work up the energy or the courage to do so.
Aquarius: They like people as a whole more than they like people individually. They have tremendous respect and faith in humanity, but can't bring themselves to have the same love for even those closest to them. They are detached, often putting more of themselves into clubs and projects than into their friends and family. They are concerned with "the greater good", and they don't let individuals get in their way.
Pisces: They will not let you treat them badly. They won't confront you or try to talk to you about your behavior. They won't try to convince you that they are right and you are wrong. They'll just slowly slip out of your life, leaving you wondering if you ever meant anything to them at all. Don't underestimate the power of a Pisces to break your heart without saying a word.