It seems sometimes like a billion people love the Beatles, but people who hate them are marked as cool most of the time (not that they make horrid music). So following that example no one would convince themselves to like a band. Besides, I've learned first hand that trying to convince yourself something is good doesn't work. I've tryed that with death metal. No go.
And to answer your second question, I used to go with the flow, and just listen the crap at Hot Topic and called it good...until I came to these forums, and they then showed me good music
Afterwards, I picked 5 albums that I liked the cover art to from a record store and bought them, and since then those albums formed my music taste, as I then got albums that sounded similar to the ones I bought before.
Through that, I've found my love for prog.
Big bang theory, if you will.