Am I officially a cold person?

My sister once told me, when we were in a junior high school,
"you share your candies with me and others
because you think you look good by doing that.
You never share them, without expecting anytying in return!
Not even once!
You've never shared them just because you want to share them."

Those words, coming from my own sister's mouth, really hurt me.
But I gotta admit that it really is true about me.

It is true that when I do things, there are reasons behind them.
When I do nice things to you or others, there are some reasons why
I should be doing such things.
In that moment, there's always another "me" getting out of my body,
floating in the air, watching from the ceiling, saying, "Way to go!"

Do you think I'm such a cruel person?
Have any of you ever felt this way before?