We share around 60 percent of our genes with bananas. From the grounds up we are built largely by the same instructions as this fascinating fruit (which is actually a berry). So are we really more than half banana?
Every living being today on earth descends from the first single cell organisms. So basically all of the basic genetic material is inherited all the way from there, from the beginning. Along the way there just have been a couple of mutations to get us this far.
Most of our genes, those that are common between every living thing are just defining the basic cell structure. It's the basic building block of all life. Everything else beyond that is just a remix of different combinations of a variety of cells.
It's all just like Legos. With a few simple shapes you can build hugely different constructs. Sure, along the way there has been some more advanced and specialized building blocks added to the mix. Something along the lines of Lego's technics line.
So no, we are not half bananas (although some of us might go full bananas from time to time). We are just build largely from the same basic building blocks as they and everything else is.