So much to say and could write a tome. But no one has time for that so . . .
Still play from time to time.

1. Praise for the engine. My toons do what I want them to do. (or did before Beamdog inexplicably broke a functioning trail finding system - but its still the best)

Of the successors, the Solasta variant of unity does the best of replicating the easy of use of the infinity engine but it's still not as good.

2. Praise for respect for rules. Very faithful implementation of 2nd rules and the homebrew rules that Bioware implements were exactly the same ones I used when I DMed (no racial limits on levels etc)

3. Praise for the replay value / non linearity. After you get out of candlekeep / chataeu inrenicus the world is open. You can follow the main plot or just forget about it for days. Weeks. A month.

4. Praise for the amount of content. Bioware tried to stuff every rulebook and every supplement into the game. I don't track hours but it probably takes me a month to complete an entire playthough.

5. Wuv, true wuv. BG2 invented the romance system. What's not to love?! Well, obviously, Anomen doesn't deserve love but otherwise . . .

6. Praise for banter. The banter felt organic. No predictable ground triggers, very few "we'll talk after the quest" moments. Instead we had a timer and randomizer - randomly out of the blue someone would say "I'm ready to talk now". Made the conversations feel more like real ones and added replay value. Of the successors, WOTR the best job of randomizing the camp dialogues. Again, adds replay value when you don't know that a conversation is going to happen on day 5 of adventuring.

Also big part of why Minsc became so popular. Why did Minsc just randomly yell something about hamsters? He's cray cray, that's why . . .