The affinity system is the measure of your progress with each character.
You primarily gain or lose affinity through your interactions with the characters in question. Characters will talk to each other, therefore actions in public places can affect your affinity with characters not present at the time. This can also apply, to a lesser extent, to actions in private; be careful pursuing multiple characters who are in the same social circles.
All interactable characters, male and female, have an affinity system. For the male characters this system will determine how friendly, or helpful, they are towards you.
There are five levels of affinity.
Negative, Neutral, Low, Medium and High.
A negative level is any amount below 0. This part of the system is purely based on your current affinity score.
Neutral is equal to 0. Your affinity with the majority of characters will start at this level. The exceptions are your Mom, because she loves you (although that can change). Your high school arch enemy (Melvin), who starts at a negative level. And to a lesser degree his older sister.
Low, medium and high use a percentage of the available affinity points against your current affinity score. Therefore, you can have a high affinity level very early in the game, but that does not mean a character will jump straight into bed with you.
Certain actions/events in the game will be available based on your affinity level with specific characters.
The level at which you transition between low, medium and high differs depending on the difficulty setting and can also be different for some characters.
Characters are generally easier to please in Easy mode vs Hard. A default setting for High affinity is:
Easy: 60%; Normal: 75% and Hard: 90%.
Example, if there were 10 affinity points available but you only scored 7. You would have High affinity in Easy, Medium in Normal and Low in Hard.
Since this is a percentage system, it is possible to claw back your affinity level later in the game if you repeatedly select relevant actions for a specific character. In the example above, 7/10 is low affinity in Hard difficulty. However, 27/30 is high affinity in Hard difficulty.
Your affinity level may decrease with some characters depending on the events you select. This is not because you’ve done something wrong with those characters, but merely an effect of not earning the potential affinity points on offer in the event you didn’t pick. The first three in-game days (Fri, Sat and Sun) are excluded from this feature.
A ‘Boost’ is a rare opportunity to increase your affinity score without increasing the total available affinity points. This has the effect of boosting your percentage level more rapidly than usual.
Note: It is not possible to achieve a level greater than 100%, even with a boost. The total available points will adjust accordingly.
You do not have to achieve a high affinity level with every character in order to play the game. You can choose to romance only certain characters.