the reasoning of sims to accept or reject hugs, flirts, etc are varied; to some degree, each EP seems to add to the complexity.
Certainly, we have the ambition and the ability to play God with our Sims, but Electronic Arts didn't try to craft a game that was made to mimic every level of detail of human society, psychology, and sexuality.
Consider the gender bias of the sims.
The gender of a Sim is specified by four possible numeric integers:
neuter: 0
female : 1
male : 2
unisex: 3
in the character's information this is given:
gender (dtUInteger) = 0x00000000 <-- has no impact on sexual preference
gender (dtUInteger) = 0x00000001
gender (dtUInteger) = 0x00000002
gender (dtUInteger) = 0x00000003 <-- has no impact on sexual preference
Also within the character file are the well known gender "preference" or "attraction" values ranging from -100 to +100.
As designed, these attraction values were meant to nullify one another in a direct and inversely proportional manner; so for every point gained for one communicated immediately to a point lost for the other.
SimPE and other game mods make it possible to set the values manually to anything you desire, but the game doesn't quite know what to do with this, since it was designed to always favour one over the other unless the values rest at zero.
As designed, if a Sim is +100 for males, the game anticipates -100 for females; even if SimPE gives us the power to set both male and female to +100, it doesn't in any way mean that the game will understand what this means and will set about doing what it was designed to do: start removing points from one to restore the balance it was designed to expect.
After the addition of Nightlife and later Expansion Packs, the addition of other factors like hair colour, perfume, stink, fatness, fitness, etc., can add a temporary bonus to the attraction, but these things have no especial impact on the values stored permanently in the character file. It seems that only woohoo -- and to a somewhat lesser degree flirting -- has any impact here, and then only when it is done with a succession of new sims.
The totally "gay" Sim, the totally "straight" Sim, and the "bisexual" Sim are all constructs that we demand for our own emotional satisfaction, but have no real impact on the Sims themselves. All they care about are what the numeric values stored in their character files communicate to them.
Also, we have to consider the impact of astrological signs. I know that these have been claimed meaningless by JMPescado and others, and certainly they can easily be out-manoeuvred by player interaction; but their impact on the relationship scores between Sims in game, albeit subtle, is appreciable and direct. In my experience, the best mixed sign pairings in order of success are:
1. Gemini-Pisces
2. Scorpio-Pisces
3. Scorpio-Gemini (but only because this is the only other possible arrangement due to the superabundance of Scorpios and Geminis in my game)
Same sign pairs generally don't work so well, but a Pisces-Pisces pairing isn't unmanageable.
Liegenschonheit has posted a graphic chart of all of the combinations here:
Sims Romantic Compatability ChartOther pairs have some reasonable similarity in being beneficial to the rate at which relationship points are gained; and since the point at which Sims may develop crushes, fall in love, and engage in woohoo is determined by the relationship scores, it plays a significant role in determining sexual preference. All of this really hinges on how much you are interfering in the way the Sims act. If you command the Sims to do things more often than you allow them to autonomously initiate things, you can end up with whatever you determine, but if you allow Sims to follow their own interests it often goes in directions you never would have expected.
Completely without any mods, I have had, at various times, Sims spontaneously woohoo when I had been made to understand they just don't do this on their own. At other times I have had a Sim develop a crush or fall in love with another Sim, when the other felt only friendship for the one in love. In one instance, it was a most curious affair since the Sim that fell in love had a preference -17 for males, and the Sim he fell in love with was male. But it was a Gemini-Pisces pairing. Go figure.
I have been looking at the
fitness preference contained in the sims' character files for the past 2 years and I really don't know if it has ever played a significant or measurable role in the game. Like the Romance score, it has been there, but I never saw where that really did much; when the Romance score was recycled for use as "light" in plant sims in Seasons EP, it clearly demonstrated it had done nothing all this time.
I have never understood if the fitness preference worked "inter-personally" or if it was a "self-state" thing. In the former case causing benefits in relationships because the sim was physically fit, or in the latter that it meant a Sim would autonomously seek out an exercise object. *shrug*
If the fitness preference plays a role in inter-personal attraction, then it certainly adds to the complexity of the way an individual sim reacts to the intereactions initiated by other sims.
After Nightlife EP, the astrological signs certainly play a much more significant role, I don't know if EA changed the multiplier or if they fixed a broken code, but it went from being totally unmeasureable on the end user level to playing a much more significant role. Although I did see it evidence some strong impact on University lots prior to NL, but even then it was unpredictable.
I understand that my observation of the game in all this time is not authorative, and many of the things I have seen don't always seem to correlate to the values easily read by SimPE in its various itterations, so even at this late date, I have many unanswerred questions about the way Sims relate to one another. I have only seen revulsion since the release of NL; but even then only rarely. According to EA (or at least their offical mouth organ Prima), the astrological signs should have caused something like this all along.
Also, it should be noted that resident Sims and sims not directly under your control are being controlled by the game's AI (artificial intelligence) - and that is a highly un-predicable thing.
Even the possition on the lot and the general environment may play a role. Certainly it does in real life, so it isn't inconceivable that EA did some small work to duplicate this.
Aspirations also play a larger role than were previously thought. I have seen several posts where people explained their difficulties of having certain combinations work. It is really far more complex than many people previously believed. The EPs make it all very difficult to understand every layer of the equation.