Well sometimes you just discover great music and find out really liking the artist
I did "bandwagon" BEP during The END era though. I'd only known few their songs and everybody liked BBP and I pretended too. But I really got into it and then IGF came which I really find great so I started like them since then
No, I only join an artist's base when I genuinely like their music. I would never pick up a new fave for their success or drop one because they lose power - note Adele's absence from my signature and the presence of Madonna and Ke$ha.