What does a Banana Smell like?

You don't need to have a comparison to know what a banana smells like -
you only need to have eaten/smelled it before to know what it is. If it smells good or bad is your individual perception and taste. You might not like broccoli because it doesn't taste good to you, but I like it and it tastes good to me. There isn't any comparison needed - your taste is the determining factor.

Ok, well let's say a banana was the very first thing you ever smelled( let's say you never tasted anything) then how would you know if it was a good or bad smell? What I think is that from your prior experience with feelings, sight, etc..those things that made you feel good from those experiences gave you a sense of what felt good or bad. And Maybe this first smell felt bad or good. Regardless of the name you will recognize this first smell based on how you feel, if not comparing to other smells, but compared to your prior feelings then.

Ok, then let's take the very first act we take in our lives. How will we know if it was a good or bad act if we don't compare it to the later acts we take?

In fact, both of you (CalamityJane and JPhil) are correct...
There are certain lines of code imbibed in Human genotypes who actually may make them prone to like or dislike a banana the first time they eat it...
...nevertheless, there is also a compared value from its taste, against "competition", once you experiment other flavours who actually might well affect and make you re-evaluate the way you describe and accept that very same flavour...

Hmm..so you're saying we have already what we like and dislike before we taste something?

Chemical balance maintenance which differs from person to person requires different adjustments in the nutritional choices we are prone to do from the very beginning ...

That is an interesting and truly philosophic question JPhil! and you have yourself given the answer above. I think that what you say is true.