The game makes an absolute distinction between good and bad answers and no matter what was said before, and no matter which idol you're talking to, if one gets the same answers to pick from, the same answer will have the same effect as everytime you pick that answer.
This makes it possible to make a complete list of answers grouped by the answers you can pick from.
Basically everything's either:
Selected char, member, member:
Mood + + + or - - - ; good and wrong answer
or
Mood + - - or - + +; or being nice or being mean to your speaking partner.
This also brings up an observation I posted some while ago on irc, namely the fact that knowing who to anger and who to be friendly to can cut down the time you're stuck at certain moods:
The short version's something like: be mean to happy people and be nice to angry people.
The fastest way to reduce negative moods is by having similar moodvalues between all characters.
I.e. after you lose to RK most people will be stuck with strained atmosphere the most common and the most logical and realistic way to patch this up would be by trying to make everybody happy.
In practice one would notice that this takes way to much time and might not even give the wanted results.
A better and more efficient way would be by reducing the distance between the 3 members by being selective mean to your sub members;
If both your members hate the leader you should alternate between picking the wrong answer for member 1 and 2 untill the distance between the 3 has been reduced or pick a good answer that raises everyones mood.
1 L 2
- + +
+ + -
In other words, alternate between being mean to 1 and 2, thus wrongly answering for member 1 will reduces distance between leader and 2 and increase the distance between 1 and 2
Continue but pick member 2 and repeat untill necessary.
For people who aren't fluent at japanese I would refrain from picking answers at the end of a day when the unit isnt at a positive mood, cause one might make everything worse.
I can get a perfectly compatible unit back to neutral from strained in 2 weeks (after losing to RK) and 3 weeks if they are compatible to some extent this way.
[Edit]
By 2 weeks; I mean the weeks one can actually influence something, sure you start with strained at w10 but you can actually do stuff counting from week 11, so the 2 weeks refer to week 11 and 12.
In week 13 everyone'll be at neutral again.
Don't worry if the danketsu meter changes to a different negative mood, it'll always be be better than a black one.
Continue focussing on who to anger and who to befriend.
[13:34] <k0sm0s> game logic