Although i find the storyline not so realistic, that is what makes it great.
Ryuji, due to his eyes, always makes a bad impression of a deliquent. Soon, he met Aisaka Taiga, the palm top tiger.
They decided to work together to help each other get their love. but soon misunderstanding appeared and Taiga ignored Ryujii to stop the misunderstanding [ only 1 episode ]

In the end[dun want to be a spoiler in the middle] They got together...want to know how? go watch the anime. It is very worth watching..

K-On is a extremely funny show, very realistic[sorta] and very good story line.
The characters are cute with different characteristics. The main character, Hirasawa Yui, started
off not knowing how to play the guitar but she soon improved and played at the school festival.
There are actually 4 main characters in the story
Guitar : Yui
Bass : Mio
Keyboard : Tsumugi
Drums : Ritsu

but in the middle of the story, or nearing the end, a new, Tsundere like[just kidding] character. Yui started to nickname her Azu-Nyan. and even randomly hugging her [ lol ]

But Yui fell sick just before the next school festival....do watch the anime if u are interested in the ending