Love In The Asylum

How much can you talk to yourself before it crosses the line into full-blown crazy? I ask merely because I realized this weekend that when I am by myself, ie when wandering around the San Francisco International Airport, I talk to myself pretty much continuously. Mostly things like "where am I going this is probably really stupid I'm going to get murdered I wonder how long it will take my roommate to figure out oh well whatever I don't know where I'm going or what I'm doing and I should really stop talking to myself seriously it makes me look crazy not like the fangirling doesn't do that anyway." Sometimes I start singing it instead. Is this normal?

Granted, I'm also the person who feels an irresistible urge to sing Irish ballads every time she gets on public transportation, so "normal" probably doesn't enter into the equation.