On my very first free champion rotation, I mained Soraka as I enjoy having healing abilities
However, after my friends told me that being a support isn't really that good pre-20, I began to play Galio, because I saw his awesome passive Runic Skin, which converted Magic resist into AP.
The tankiness I got also helped me to learn how to lane better.
On the next day, after a bot match, I loved Lux and I bought her, mainly because of her laser beam XD
Also she had a huge range, and that gave me an advantage on most mid laners, and I like having advantages
Then after a few weeks, while I was reading a Lux guide, I saw LeBlanc as one of her counters, and I waited for ages for LeBlanc to be in the free rotation. Then she came into free rotation. After 2 bot matches and a lot of studying XD I was doing really well with her, and so I mained her.
Now my mains are LeBlanc, Galio and Lux
I lost my ability to play Soraka after I stopped playing her for ages