I've seen a lot of websites and a ton of hate fics for Rini! I used to not like Rini that much either, but I never hated her. One day while I was looking around for Wicked Lady pics (that's Rini's evil form!), I came across a Wicked Lady Shine site. This one section was dedicated to 'Small Lady' (aka Rini). There they said some interesting things that really changed my views on Rini to the point where I feel like I have to write this little thing to her. Most of this rant is more on the first time she arrives in the series--and Rini's image changes when she comes back older and a Sailor Scout.
Rini isn't that bad, and once you understand her you can't possibly thinks she's all that bad. She's just a little girl when she came into the series. She wants the Silver Crystal to take back to the future to help her mother--which is Serena (aka Sailor Moon). She may be bratty sometimes, but aren't we are? I'm not going to say that she has every right to be bratty, but she's using the bratty image to keep people away from her. Her mother is trapped and her father is wondering around the palace. The Sailor Scouts--minus one Sailor Moon--can't help her and she has no friends to mention. She's left alone to wonder the palace! That's a said life! And arriving to the Past, Serena's starts off yelling at her.