>>122113658>Patty can easily befriend someone else. Doesn't she have Franklin already? Her entire baseball team? Why stick with Marcie at this point?Franklin, Roy, Linus, and even Charlie are, ultimately, still boys. A huge part of Peppermint Patty's character stems from not having a mother, so she has no guidance or help on basic functions girls go through. If you think about it, Marcie is the only female voice Patty has to turn to, especially when things of that nature really bother her (physical insecurities, struggles with femininity, and the crush she has on Chuck).
These are avenues that a mother would typically help in, which Peppermint Patty obviously doesn't have. Marcie is invaluable to her, no matter how much she may annoy her.
Likewise, Patty helps Marcie be more outgoing and gives her a chance to mellow out from her otherwise overbearing life at home. While there are undertones of annoyance, passive-aggressiveness, and competition between the two, but the friendship itself is still beneficial to both.
Both care about each other, too. Schulz wrote a very realistic and endearing depiction of female friendship.
This also makes the love triangle both girls have with Charlie Brown pretty tragic. Each is stubborn enough that should either win, the friendship would break. 
