Why start threads like this?

[katya]

EDIT: See a couple posts down for the real reason behind this thread.

So, I was at another message board and I noticed a couple "best ___ of all time" threads, namely one concerning first person shooter video games, but it could've just as easily been best movie, best band, etc. My question is, why start threads like this? What is their purpose?

Firstly, how can you say something is the "best"? You could take a movie, say, and rate it according to various different factors like plot, visuals, acting, etc. and pick that way. However, most people who reply to threads like that are going to pick their "best" based more on things like which movie they have fond memories of, the best movie out of their limited viewing history, which movie had a character they thought was really hot, etc.

Then there's the threads themselves, which usually end up with people posting only the title of their favourites over and over, and really don't seem to serve much purpose. Who wants to read something like that? Why do I care what movies everyone else likes and why they're so great? Or books? Or FPSs?

I'm not saying it's stupid or ridiculous or anything, mostly I was just thinking about what motivates people to start and post on these sort of threads. What is it that makes us immediately want to share our own favourites with everyone?

And do people actually care to read them?