Bunnies can be surprisingly scary. There are two pet stores near me that sell bunnies/rabbits and they always grunt and run away when people walk by.
I think pets in general have associative memory. Animals understand on a simple level things that are good, and things that are bad. Bunnies at the pet store or bunnies that have been mishandled in the past associate humans as bad because of their lack of interaction and experience, or due to bad handling.
Remember that rabbits are prey. Even if you’ve never been mean to your bunny, their natural inclination is that you are a predator. And they’re right, we’re predators.
From my experience with a variety of pets including currently a bunny, I think the best thing you can do is work toward creating an association between YOU and something GOOD.
But don’t start with pets and other touching that they might not want. Start with something all bunnies and living things need. FOOD.
I’m not saying deprive food from your bunny, but when you give treats, always give from your hand. You are the hand that feeds. You are also the hand that brings treats. Eventually your bunny will come out of his or her shell and realize that when you’re approaching, he or she will get a treat.
Don’t leave treats in the cage for your bunny to get for him or herself. When you do that, there’s a chance the bunny just think it happened across the treat and won’t associate it with you. Make sure when your bunny is eating that piece of banana she loves, she’s simultaneously smelling your scents and being very close to you.
My bunny only has unlimited access to hay. I feed pellets and other treats exclusively from my hand. My bun was super shy and extremely afraid of humans, but now, he’s jumping up on two feet to get to the goodies in my hand.
Try that for a while, it might take some time, and good luck!
I’m so glad to hear you have a bun that was mishandled in the past. You can show it that there are nice and loving humans too!