lubbockleft: Zlata does not cure "sad," but she can talk to characters that are depressed and remove the depressed status. It makes a new icon over their head if you have her and a depressed character. Depressed characters are at risk of killing themselves, so it's a useful skill to have on your team.
I think the spirit of discovery is part of the enjoyment of the game personally. Even misclick combat deaths (my biggest problem) simulate modern combat when you think about it :P
No, anyone can talk to people who's parameters are getting too low. She's just better at it for the happiness levels.
I've had two depressed characters, Roman and Marin. I had a bottle of alcohol in the fridge. While having Roman selected, an icon appeared above Marin to share alcohol with him so they both ended up drunk off their heads.
Same goes for someone who's starving, really sick, really hurt. Other people can interact with eachother depending on these parameters.
Bombastic: Ok, some people will say "Ah! This game is simple, you need only click action icons!" ...
Ahaha... Very simple indeed, except that there's a lot of things that you don't know what they are and you cannot know every possibilities about this game!
For example, what is the use of the icon near the bandage and medicine ones?... What is its use?... I don't know!
Is it possible to feed someone who is sad and can't move or to heal him/her?...
How you know to go in garden and plant some stuffs to farm food?
How to barricade house, etc etc... There's so much questions where you can't have answers!!!
There is a wiki dedicated to the game... maybe you can look there?