Aries (March 21 - April 19)
Although Aries is an extremely loyal friend, they're natural leaders, and leaders need followers. They tend to be self-involved and impulsive, so they go through great lengths to defend themselves during a confrontation, even if they're in the wrong. You need to be incredibly patient to deal with the temper of an Aries.
Taurus (April 20 - May 20)
Taurus is the dependable but often judgmental friend. But in the typical Taurus way, they're too stubborn to admit that they've done something wrong if you tell them they've hurt your feelings. Taurus can also be possessive, even with friends, so be careful when they flash the jealous eye at your other friends.
Gemini (May 21 - June 20)
Energetic yet superficial, Gemini is one of the proudest of the signs. They make for exciting friends because there's always something new going in their lives that they absolutely need to tell you. However, they can make you feel low when they try to one-up your accomplishments with a better one of their own.
Cancer (June 21 - July 22)
Loyal and nurturing, Cancer is the friend that will compliment you, listen to your woes, and encourage you through the hard times. But sometimes, they can smother you with their care, making you feel like you have a parent rather than a friend. Although they care so much about their friends, they also have a secret desire to be cared for. But they would never tell you — you'd have to figure it out yourself.
Leo (July 23 - August 22)
Leos are surprisingly very loyal and encouraging friends. However, they have huge egos that rivals that of Aries, and they tend to be very controlling. In order to avoid the ire of a Leo, as a friend you constantly have to compliment and shower them with attention so they can bask in it.
Virgo (August 23 - September 22)
Analytical and observant, Virgos can only be described as the know-it-all friend. They're meticulous and strict with schedules and things being in their place, and if you stray from that, they won't be happy with you. With Virgos, remember that it's their way or the highway.
Libra (September 23 - October 22)
Although Libras have a penchant for diplomacy and hospitality, they also have a vain and superficial side. Libras have very high expectations for everyone, including their friends. If you don't meet these expectations, they become distraught. However, like Cancer, they tend not to talk about it, preferring that you figured it out yourself.
Scorpio (October 23 - November 21)
The most mistrustful of the signs, it takes a lot to gain the friendship of a Scorpio. Although they're loyal friends, they still have an air of skepticism toward the people close to them, so tread carefully around your Scorpio friend. If they suspect you of betrayal, they have the ability to manipulate you into telling them, or figuring it out themselves. They're pretty much in control of the friendship.
Sagittarius (November 22 - December 21)
The most free-spirited of the signs, Sagittarius can be emotionally detached from their friends. Thus, they'll always say exactly what they're thinking and will feel no remorse if it hurts their friend. Unlike Aries and Taurus, they have no need to defend themselves, because they believe strongly in their opinion. As a friend of Sagittarius, you have to remember that they run through life at their own pace and time, often with less or no consideration for you.
Capricorn (December 22 - January 19)
Although a loyal friend, Capricorn tends to be proud and is the most independent of the signs. No matter how caring they are towards their friends, they still hold this air of authority. They aren't welcomed to other point of views, so there's no use arguing with a Capricorn — they simply won't budge. Like Sagittarius, they don't feel the need to defend their actions and opinions.
Aquarius (January 20 - February 18)
It's actually rare to find a toxic Aquarius friend, but they're clever and stubborn. Due to their rebellious streak, they can be emotionally-detached from their friends. They won't force you to do something you don't want to do, but if they're upset about it they won't tell you, which can be very frustrating.
Pisces (February 19 - March 20)
Pisces are the most passive of the signs, but with a secret aggressive side. They're observant and can figure out what ticks off the people around them. As they're also incredibly sensitive and emotional but won't tell you, it's difficult for you to figure out why a Pisces is acting the way they are.