It really doesn't bother me.
I left home at 17, and it's been 36 years since I lived even within 100 miles of my family, so I'm used to it by now.
They treat me like the prodigal son when I go to visit them, and always seem sad to see me go home, but once I'm away, I know I will never hear from them unless I make the effort to call or email.
But yeah... being introduced to my mom's friend, and the look of shock and confusion on the lady's face when she said 'I didn't even know you had another daughter!' was pretty classic!