Your last sentence is spot on for me, scarily accurate even. Im not gonna be an asshole but I know for a fact no matter how nice they seem that theres a huge probability they would be trearing my past self differently so i do the bare minimum for them - with the exception of very few people that im truly close with and they have proven themselves.
Also when it comes to dating. I know it can get you a lot of hate here but the way I see women has changed for the worse. My confidence didnt change, my manners didnt change, actually nothing changed except from my weight (and i wasnt morbidly obese btw) but suddenly I am now interesting and have a lot of options to the point where I can choose while before I wasnt. Meanwhile men AND women try to bs each other that personality is so important and looks secondary. So until I find the person that I feel is truly compatible and relatable to me, Ill just take whatever I want whether thats sex or sometimes company being fully aware that they wouldnt bother with me before I had my "glow up".