The best part of Dragon Age is that the characters on your team will randomly start talking to each other as you're walking around - different conversations depending on who is on your team. No matter which companion is talking to which, it's always the same amount of hilarity. It helps that the voice actors are utterly superb.
The level of detail in this has changed the way I look at video games. The writing... is perfect. And so thorough. I am learning so much about how dialogue trees can be put together just by playing this. How they give the player information while at the same time letting the player feel like the information dump is interactive (even when it truly isn't at times - sometimes no matter what you choose, the person you are talking to will say the same thing, but since you're given three differently characterized options to choose, it makes you feel like it's more interesting). It really feels like these characters are your friends because they respond to you and follow your lead in conversation. If you joke around with Alistair, he'll love you and joke back. If you mock his feelings, he will remember it and hate you. You only get the option of having certain conversations once, like real life. Decisions you make really have an effect on the gameplay.
They cover every possible character combination, even on things you can accidentally skip. From the little I know about writing and programming, for each pair of characters to be able to interact together, depending on who you choose to do a situation with... that is an incredible amount of hard work.
Like I guess I skipped these complicated, hilarious bluffing situations by being a hero and breaking myself out of prison:
Click to view
Just... crazy. The average player would barely even see one of those combinations during gameplay. And yet, so much work. It makes me so happy.
My favorite = 3:20... ahahaahaha Sten you are my favorite ever made (why am i not allowed to romance you)