I've never believed people can change; circumstances, yes, people, no. We are what we are from birth until death, and people tell you everything you need to know within five minutes of meeting. Yes, experience can temper attitude, people mature or deteriorate, but beyond that?
It is wise to listen to the stories people tell. Whether truthful or fiction, the future of your relationship is all contained in the introduction.
Throughout my life I have hung out with charming reprobates, and while this choice has proved exhausting, it was, after all, a choice. Hooking up with thieves, liars, people I have evicted for good reason - hardly surprising that mayhem ensued. Heck, the first time around I married someone I met in criminal court; the consequences were easy to predict.
It is certainly true that I am exactly as advertised: acerbic, irascible, obstreperous. Caustic. Scrappy. Mean. Tricked out with long hair, lipstick, and cleavage. Some people like that sort of thing, but they are hardly ever the ones I want to talk to.
Oh, and the fact that I use words like truculence and remuneration in ordinary conversation has never had any beneficial impact on my life. Just saying.