I think a typical way is a skid being careless.. intentional.. abusing the SP's belongings.

Nonstop micromanagement and snarky comments

Stubborn but indirect noncompliance with rules, refusal to cooperate

Incessant complaining and sulking

Stealing to even the score

Sneakiness and lying

Refusal to answer questions

Baiting and then playing the victim 

Constantly disagreeable and argumentative

Walks away while being reprimanded

Purposely annoying everyone

Withholding affection in order to punish

Gaslighting

Gossiping to BM

For example, last night at dinner with my parents, at an expensive restaurant, Sd16 Backstabber/Munchkin decided to put me on the spot as to the login credentials for her class registration which is all online now. I had gotten a notice emailed to me, created the username and password and sent all in a text to Husband who told me "ok. You do too much". Well after freshman year when I was asked to help out and them totally b!tched out when I did, I wasnt up for engagement over this. 

When she asked for credentials, all I said was "I texted those to your father. He can give them to you, just dont change the password." She got mad, went silent, looked down at her (expensive) plate, hunched over and pouted.

Last weekend, I poked the bear and texted SD23 Feral Forger that she needs to not blame others for her problems and that I was not to blame for her lack of relationship with her father, SHE was and she needs to take responsibility. Her response "I hate you F@ck off, you f@cking horrible stepmonster!!!" Some other things were texted and I ended with "sending you blessings and wish the best". Then block block block.

She would do things like shun me in my home. Husband either didnt notice of didnt care. I would go pick strawberrries and have some in the fridge, SD23 would stomp in the kitchen and ask husband if she could have some strawberrries, he would refer her to me and she would growl and stomp back off not asking me anything. Stuff like that.

And she does relational aggression too. She will try to get others, like husbands family, to hate me too. 

For me, carelessness is at the top of the list. I also think one of my SSs does things on purpose to bother me, like turn all the lights on in the house or put the toilet seat up even if he didn't use the toilet. He also ignores me, which I don't mind, since I find him annoying, but it is weird for someone to be sitting there and looking past you. 

They also both constantly criticize things at our house or tell DH and I what we should be doing. For example, the latest thing is that MIL complains to SSs that we "never" invite her over...but she "never" invites us over and "never" gets in touch with us about anything. Also, why would I invite someone over if she tried to use my skid to get me to invite her over. That is the exact wrong way to appeal to me. 

One criticizes everything that DH does and both are rude and disrespectful. I was glad that DH finally called one out this weekend when he said, "what's your problem, bro?" after DH told him he couldn't light a fire in the fireplace in the middle of July. 

Both also regularly complain to BM about how lame or boring our house is and tell her we don't give them the things they need. 

One also lied to BM's family and DH's family and told them that DH and I both sit around and talk about how much we hate BM. 

I think sometimes what hurts more is not intentionally being excluded from things but they just didn't consider you or your feelings.

It took me four years to decide to just not host or arrange anything with/for them. The final nail was two of them showing up to a birthday brunch my bio son hosted for me and invited the skids to,  an hour and a half late and then being the first to leave. Message received. We are not talking occasionally being late, it was constantly being late, to every single event we hosted. OSS was the most egregious but they ALL take turns. 

This is an excellent topic. I could write a book of small rude-ities. No single event is all that horrible, which makes it impossible to convince DH of the accumulated level of disrespect and abuse.

One of my personal favorites: SS, DIL and two SGDs are here for the weekend. We tell them what we have on hand for lunch, make them each a custom plate, youngest -- who's four -- throws a huge temper tantrum, kicking, screaming and refusing to eat. Parents act like no big deal. So...okay. We clean everything up and go about our business. Half an hour later, I walk around the corner and find SGD, standing on my kitchen counter in her outdoor shoes, being handfed her own private lunch by both SS and DIL.

Honestly, it wasn't the temper tantrum, it wasn't the lack of parenting (okay, it was a little), it wasn't that she got handfed later, it was that she was on my counter in her filthy shoes. Which would never in a million years happen in her own house.

I wouldn't call what SD15 does to me abusive, just rude. She pretends like I don't exist. It's amazing the lengths she will go to to act like I don't exist, like asking about each of our kids, and pets, and friends, but not me. Or if I try to talk to her or engage in a conversation with her and DH she just ignores me and talks to DH. He doesn't notice this because he's still getting attention. Now SD and I mutually ignore each other. I think she's coming to regret it because she's taken an interest in the field I'm in but I AM NOT going to help her with her homework or college. It makes me feel used that you suddenly want to talk when you have homework I could help you with. Read the book. 

"I dunno."

"I forgot."

"Sulking silence."

My SS wasn't too bad except during pre-visitation behavioral degradation (~7-10 days pre departure) and post visitation behavioral detox (~2-3wks post visitation).  Our CO stipulated a long distance visitation schedule which they took intermittently so we did not have to deal with it constantly.

Thats their choice of weapon. Subtle, hard to pin point, and most of all daddeee warbucks never sees it.

Last time I was at his place, his daughter didn't come out of her room. I'm not prepared to move so I need to travel an hour each way for work only to feel uncomfortable every weekend when she comes and treats it like a hotel - checks in Friday, orders room service, has the maid (his mother) provide turn down service!

After i teasingly poke sd thinking we're having a bonding moment and then she DIGS her fingers into my side as hard as she possibly can (contorting her face so i know she's giving it her all) <-done multiple times

Her SHOVING past me SHOVING me into the door frame leaving a bruise on my arm for weeks. 

My SD doesn't invite me to things. His family will even ask DH if he wants to go do something but leave me out. For instance for SD birthday lunch in April, I wasn't ask so I ask my SIL if I was invited and she said let me check with SD. SD said it was fine and I was able to go. I noticed this stuff happening more and more. Of course DH doesn't notice this because he's got his head in the sand like an ostrich, which is BS. But SD won't engage with DH when I am in the room or she'll talk very softly where I can't hear. She's very rude but yet she'll go cry to SIL that her dad doesn't do anything with her. I get blamed for it and I have never stopped DH from spending time with his kid. But SD sees it that way. If I ask her about something she said she was going to do, she gives short generic answers. So, I don't talk to her that much. She acts like a victim instead of looking at it like she's part of the problem. My counselor said they are both putting me in the middle or their problem.