What Does It Mean to Have a Favorable Opinion of All Members?

It's a single heroine, there's no harem I was created into a parallel world by the Universiade, and I found that this world was a little different from my world. How could I switch bodies with my deskmate who is cold on the outside and hot on the inside? Why do I still have an adopted sister who was adopted by my parents? What different relationship do I have with Qingmei in this world? He also dyed his hair yellow and rode a will-o'-the-wisp? How can things still happen that cannot be explained by science? Why is this favorability system useless? I'm chovy, I've been dressed for time travel, what's going on! Favorability is only useful in the early stage, and is basically useless in the middle and late stages.