Did you know that banana is yet green when already good for consumption? It is better if you buy green bananas in the shop so that you have more time to wait eating them.
Always have a look in the store before you buy fruits. If you know that you will eat it at day of buying you can buy ripe ones which others maybe would never buy other way.
Or buy those ones which have some days to get mature status. In case you take a banana next to not mature yet fruits, it will gain them to get mature.