(A few spoilers below)
I hate when people say Piper is useless
Piper has got to be one of my favorite characters in the series, she's a great character and she isn't useless even though a lot of people think so.
These are a lot of STUPID accusations against Piper.
1. Piper is so whiny!
Really? REALLY?! The only time in the series when Piper was ever whiny, was in The Lost Hero. Her dad was kidnapped, she found out she was a demigod, and went on a quest immediately. Imagine if one of your parents or guardians or someone you're close to was kidnapped. Chances are, you would probably whine more than Piper McLean. Another thing to take notice of: she barely ever did whine, and when she did it was to herself because she didn't want to burden her friends with her problems.

2. She stole Jason from Reyna
Reyna never was Jason's and Jason never was Reyna's. They had a bond but Jason never had stronger feelings than that for Reyna. So no, she did not steal Jason from Reyna since they were never a thing. (Sorry Jeyna shippers)
3. Piper thought about betraying her friends
HER DAD WAS KIDNAPPED MY GOSH! If you're one of those Piper haters, answer honestly to this question. If someone you loved was kidnapped and was to be killed, and the only way to save this person would be to betray your friends, would you consider it? If you answer no you just failed Candor iniation and you are now factionless.
Get this, Piper didn't betray them.
4. Piper's too obsessed with Jason
. . .
Yeah she may be obsessed with Jason.
OH COME ON YOU GUYS ARE OBSESSED WITH FICTIONAL CHARACTERS AND SO AM I, LET THE GIRL OBSESS OVER HIM
AND ITS ADORABLE
5. She's such a Mary Sue
Just because she's pretty and can charmspeak, people say she's a Mary Sue.
Lemme share a little secret.
SHE'S A DAUGHTER OF APHRODITE SHE'S SUPPOSED TO BE PRETTY AND CHARMSPEAK
She is no Mary Sue
And she HATES looking pretty, she did everything in her power to make herself look uglier.
6. She's a downgrade of Annabeth
The two don't have much in common except for bravery, so you can't compare them really. Gosh . . .
7. She doesn't do much except obsess over Jason
Hmm, really? So you're saying she didn't save Percy and Jason's lives several times? That she didn't charmspeak Festus into waking up? Perhaps she didn't defeat Khione. Or the Eidolons. Or save them several times. Maybe she didn't get her cornucopia from Achelous and save Jason and Percy from drowning. And maybe she didn't charmspeak Asclepius into giving her the physician's cure which SAVED LEO'S LIFE. She didn't so all of that plus more? Uh huh.

Alright, I'm done because what people come up with is infuriating. And I'm tired.
*hands out cookies*