If someone asked me that, there's a good chance I would say "no thanks" right away. It's not that I don't like bananas-- I like banana ice cream, my favorite dessert is made with bananas, and eating raw bananas isn't messy. I even like the taste of bananas on cereal.
I say "no thanks," then, as a habit developed over many breakfasts in highschool. I must have decided that breakfasts should be low-effort; no time for chopping bananas. Once I started turning down offers of bananas, there was no going back. My parents, however, kept kindly offering fruit for cereal probably until the day I left for college.
Saying "no" as a default response isn't restricted to cereal toppings. I've missed a lot of opportunities by saying no to things before properly thinking about it. Thankfully, new chances do appear, and by acknowledging my biases I can try and change them. If I had breakfast with my parents today, they would probably ask if I wanted fruit on my cereal.
And I would say "no thanks," because really, who has the time to spend 30 seconds chopping up a banana?