My SIL (or Sister Outlaw, as I've privately nicknamed her after she and her DH had their illegal operation busted this year) is a
blizzard. I have countless SS stories about her, but that would take hours and traumatize everyone, so here's a little one.
Two weeks before my wedding to her brother, SoL was in Ourtown visiting my SMIL and FIL. She called me and didn't ask,
told me that her eldest daughter needed some jeans shortened, and that she was going to drop them off at my mother's to have my mother take care of the job. My mother is a very talented seamstress, and was sewing my wedding dress, my two bridesmaids' dresses and knitting us little shrug sweaters to wear over them, which SIL knew. SIL had met my mother maybe twice at this point, and had talked to her once on the telephone.
"Well, that won't work right now, SIL, because she's really busy finishing up the wedding clothes," I said, thinking that even if she'd forgotten that my mother was extremely busy with this huge gift for me, it was pretty presumptuous for her to assume that Mum would leap at the chance to do busywork for a near-acquaintance.
"Oh come on, she doesn't have 10 minutes?" SIL snapped.
"Not right now," I said truthfully.
"Fine,
thanks," SIL snarked, and hung up.
10 minutes later, I get a phone call from my Mum.
"Did I tell SIL that I would do her kids' mending?" she asked, genuinely puzzled. SIL had called her after hanging up with me, and attempted to badger her into doing the job! No "please," no asking at all even. Just "I really need this done," with the distinct attitude that my mother was the "help."

Fortunately, Mum has never had a problem with "no" as a complete sentence, but she was baffled at the entitlement.
(SIL has a history of staging bizarre crises just when large events are happening in others' lives. DH and I just bought our first house, so right about moving time, she'll call for something, I just know it.)