Interpret this.

[TheHouseElf1]

So this is an excerpt from a text. I would say read between the lines but I don't think it's necessary.

"I spend large amounts of my life being kind just to be kind. It changed me as a person I think. I think the way you speak and interact (with me, the girls and the wider world) has become a habit and that has become the norm even though you can be kind when you consciously think about it."

So is it just me?

Are you a massive cunt?

Some people are. Me included probably.

I think whoever sent you that is trying to tell you to make the effort to be a bit nicer to people but without hurting your feelings.

I wouldn't take offence because it's very sensitively and tactfully worded. However, I would take heed because this person obviously cares deeply for you and just wants to see you be the nice person they know you are, but more of the time.

Christ I've turned into the rainbows and smiles cake bint from Mean Girls

Some family members can get in a habit of just not being nice in their everyday interactions. Nothing really specific, just the impression that you are being tolerated rather than loved.
OP - do you genuinely love and cherish the person who wrote this text? Or are you grumpy with them? If you are so you have good reason to be? It's ok to be grumpy with someone who niggles at you or doesn't pull their weight or is critical.