The romance between two characters can be complicated enough, but when you add a third person to the mix, things get infinitely more difficult - and for some fans, more interesting. Love triangles usually involve two characters who are both in love with the same person. They might get competitive with each other, or one person might step gracefully to the side, but either way, there's definitely going to be some hurt feelings.
One popular example is the love triangle between Tohru, Kyo, and Yuki from Fruits Basket, in which both boys slowly come to terms with their feelings for their new friend. If you're looking for something significantly less wholesome, there's Makoto, Sekai, and Kotonoha from School Days, in which two very dangerous girls are pushed to their limits by a philandering jerk.
Whether you're looking for something adorable or something disturbing, there's probably an anime love triangle on this list that will spark your interest. Which ones are your OT3(s)?
At the beginning of Fruits Basket, both Kyo and Yuki seem romantically inclined toward their deeply empathetic new housemate Tohru. Eventually, Yuki realizes that he only ever saw Tohru as a mother figure, and ends up falling in love with a girl named Machi instead. Meanwhile, Kyo and Tohru are basically engaged by the end of the series.
Kagome is technically Kikyo's reincarnation, so it stands to reason that both of them find Inuyasha appealing. The problem is that while Kikyo and Inuyasha were once so close that they were literally bound together for eternity, Kikyo actually sacrificed her life to keep the Shikon jewel sealed, leading Inuyasha to move on and find happiness with Kagome. When Kikyo is reincarnated, she loves Inuyasha, and gracefully stepping aside isn't easy.
Yuki Kuran has two potential love interests - Zero and Kaname. She has an extensive, complex history with each one, and actually ends up having a daughter with each of them. Kaname is her brother, the person who rescued her from a Level E vampire, and the person who holds the key to her mysterious past. Meanwhile, Zero is a vampire hunter (and vampire himself) who Yuki bonded with in their early teens.
When Naruto begins, the dynamics of Team 7 are drastically informed by the love triangle between them. While Naruto harbors a huge crush on Sakura, she's totally disinterested because she loves Sasuke. Meanwhile, all Sasuke cares about is getting revenge on his brother. Eventually, their feelings shift, with Naruto falling for Hinata and Sasuke warming up to Sakura by the end of the series.