If I had a chance to change anything, I'd  have created a mutated strawberry. It would be as big as a watermelon, as sweet as a strawberry might be and it would be delicious! Can you imagine eating such a strawberry? Bigger than your head? Delightfull! How many shakes one could do from such a giant fruit, I can't even think of it:)
It would probably also need a lot of work and endeavor but it'd be worth it. Of course I'd then after some time sell it to someone influential who knows how to do bussiness, and then I could do anything because I'd be rich then. I could do everything I ever wanted: travel all over the world, establish a charity, build a house at the seaside and all those impossible things from my dreams...
Wouldn't that be nice? :)