Something that my extrovert friends don't understand is that when I know I'm going to have an evening, or a day, or a weekend on my own that scheduled alone time is just as important to me as any social event that I have committed to.  


It is difficult when someone wants me to do something and they just don't understand that just because I have nothing social planned for that time that that means that I am available.  I'm not.  I'm hugely disappointed if I have to miss expected alone time.