As the oldest child is special to the parents for being the 1st, and the 3rd child is special for being the baby of the family, the middle child is never the favorite child.
-quiet around family but fun with friends
-feels a need to defend people outside of the family when family criticizes someone
-have a sarcastic personality
-lots of common sense
-not as close to their parents as the other children are
-left out of activities
-does not like to join in on something unless specifically invited
-don't feel like they can talk to others openly when their family is with them
-sometimes wear sunglasses so that they can cry without anyone noticing
-dress, write, talk and act more boring than they would like for fear of criticism from family
-deal with a lot of bitterness
-sometimes named after a dead relative no one really knew
-hate being compared to relatives
-finish eating before everyone else at dinner and disappear
-oidentify with and sympathize with the villains/bad guys in fiction. (Loki, Darth Vadar, etc...)
The middle child often feels isolated and detached from their family. They are eager to leave the town they've grown up in. Middle children often long for true love and a family of their own so that they can try to "make up" for the way they were treated by treating all of their kids equal.
Middle child: So Mom said she isn't going to take me to that campout after all... *sigh*
Oldest child: Oh, sorry.
Middle Child: It's alright, what do I expect? I am the Middle Child, after all.