Our choices do matter to our experience, though. If I started telling everyone on Hubski to go fuck themselves and spammed pictures of goatse I'd end up muted and hushed by the whole damn site pretty quick. All the little choices we make affect our lives in different ways.

Other games actually do what Mass Effect pretends to do here with dialogue. I've been playing a lot of Baldur's Gate (I & II EE) lately. Now there's a game where most of what you say matters. The same can be said of Torment, or of KoToR or Fallout. Most conversation-choice heavy games, the ones I"ve played anyway, tend to tie conversation choices into the plot or into the outcome of particular scenarios to a much greater degree. You get a handful of choices like this in Mass Effect, but the vast majority of your conversation may as well not happen as far as the plot is concerned. You won't change much by just mashing your way through it.

Like in Baldur's Gate right now I've actually got two games going. In one my party is super evil and I'm constantly fighting guards or bribing priests. In the other I occasionally do something crazy but I've been mostly heroic. They give you two significantly different experiences of the game. Characters say different things to you, prices are different, some people who would aid you in one situation will attack you in another. Even your stats affect dialogue.

I mean, come on. It's only like 4 times as much writing. ;)