Sarcasm a sibling thing?

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Growing up in close proximity to my sister I had to develop some sarcasm just to survive through to dinner time, and so did our younger brother.

It seems these days that we are all at our best - banter wise, when together. We are rarely all together, my siblings never meet up without me, I am a true middle child in that I have a (mostly) great relationship with both of my siblings and yet the two of them barely make an effort to keep in contact, and I like nothing more than bringing us all together.

My brother-in-law will sit as though at a tennis match when we get together, he says that my sis, although still with a wicked sense of humour doesn't banter with anyone else the way she does with me, he himself is a very laid back relaxed man, who says very little.

My sister-in-law-to-be will join in when the challenge is to put my brother in his place, but she is not quite confident enough to send any barbs in the direction of the sisters - not yet anyway, although I do look forward to that day.

Few of my friends would say I was sarcastic, its rarely shown in my current life, but when I find myself with a worthy opponent, well then I really enjoy the banter.

So I wonder, even though we are rarely together is there something about growing up with siblings, feeling at ease with the banter, giving as good as we get and surviving to challenge another day, that allows us to easily slip back into the role, no matter how rarely we spend time together.