First, you got good advice from senior cat handlers (hissy and dragonlady).
Second, cats, like people, react to what they see as traumatic and threatening events. I rescue street cats -- mostly they come to me as young kittens between 3 days old up to around 4 months old -- and they enter a household that normally has between 15 and 25 cats of various ages and temperaments and 6 adult dogs (although at the moment I have two puppies from the street as well).
This kind of household, since all the cats and dogs are uncaged except for the perimeter fence, can be a big shock to older cats. Except for the very young cats (who, like children, tend not to remember their earliest experiences), almost all the cats have had some kind of traumatic experience, and since they are ingenious about getting out of the garden, they also add more contemporary trauma to the old. They respond very much like your cat. The most important thing is to be patient, and then again patient. Then you try to figure out exactly what stimulated their fear. It can be another cat trying to put its temper onto younger, less experienced cats. Other times the cat has been chased by a dog outside the garden, or been confronted with a sudden change in its environment -- even moving a piece of furniture the cat is used to jumping up on will set off some cats for a time. But most often in my household it is pure irritation about the introduction of yet another strange cat or puppy.
Every time I introduce a new cat or puppy, I go through the routine of putting the newby into a large carry-cage near a wall (not in the thoroughfare) so all the cat and dog family members can get accustomed to the newcomer's scent. The first day or two, depending on the age and disposition of the new cat (or the perennial jealousy or fear of an older at), there is a lot of hissing, approaching and backing up, fierce eye-to-eye contact, etc. Sometimes older residents will hiss at me, or take a swipe at me when I am feeding them, or ignore any overatures of affection from me. This is all normal. The oldtimers can be just as traumatized by seeing strange cats on the wall that surrounds part of the garden.
The best case is that they hiss a little for a few days and then just keep their distance from the newcomer for a few more days or weeks, and then either ignore the newcomer (as not one of THEIR circle) or decide it's OK to sleep together in the traditional cat and dog heaps on the bed during the day. Sometimes they will accept the newcomer and then a year later (still holding a grudge for its arrival) wander off to live with a neighbor for a while in case I didn't understand how irritated they were with me.
Patience. In my experience, half of the cats who go off and find new caretakers come back after a time -- one cat recently returned after 3 years. So it is clear that cats remember their friends, and also remember upsets and emotional hurts, and that they, like humans, have to think the situation through before they accept it.
And finally, YES, calicos in my own experience, and in comparison to all the other types and colors of cats I have cared for over the years, have very uncertain tempers, can be insanely jealous, and can bear grudges for years. The longest jealous grudge was held by my calico matriarch (the first female cat I had here in Israel), who took offence when I started to rescue the many abandoned kittens in my village. From the first day until two years later, I could not touch her at all. Then over another two years I gradual worked up to very brief pats on her head, then her shoulders, and then her back. To this day (now almost 6 years later) she will not permit me to touch her stomach, or under her chin, or near the base of her tail, nor can I pick up her feet. On the other hand, she shows in many ways that she understands my affection for her and appreciates it. But her bottom line is that I severely wounded her pride and she simply can't let it go entirely.
She is always the unstable element in the family now, lashing out for no reason at all at one of the other cats or dogs who pass too near her when she is resting, but she has stopped lashing out at me directly. It is sad that I can never hold her again in my lap, but I have tried in every way I can think of over the years to give her as much or more attention as she will let me. And at night, she has begun to sleep on the bed next to my pillow. I had to put away my own fears of getting her claws in my face at night. That took me a lot of self-control. But I was right to brave it out -- this change of her sleeping place heralded a forward positive step in her behavior toward me). I put a towel by the pillow, and she immediately accepted that as a signal that she was welcome. Woe to any other cat who inadvertantly puts a foot on the towel. But vast improvement all around.
So patience, the constant emanation of love and affection (not just the words and your voice, but the feelings, since cats can usually figure out what you are thinking), and more patience.
With other cats, the job is usually not as difficult as it is with an offended calico.
A word about other traumas. I can always tell when the cats have had a run-in with a neighborhood dog, because they come home and shy away or hiss at the dogs in our family for a few days. Usually the older dogs, who have all taken turns as surrogate moms (even the male dog) for one or more of the cats, are touchingly patient and gentle, and the situation is OK after a little while. They can be shocked into several days distrust by loud noises, inappropirate happenings (like my inadvertantly turning the garden hose on them), and the smell of strange animals. We have had jolly aftermath temperament when I rescue hedgehogs, birds (mostly young egrets who fall out of their tree nests), and snakes.
So a lot of things set them off, and many times you don't have a clue about what it is. You just have to love them enough to give them the space to think the situation through, and then the patience to reestablish the trust you share with each other.