I was just bored so I wrote this. It's just a quick thought if Wally and Artemis never liked each other in my opinion.

They argue even more than usual and Artemis is willing to kill him though she can't because hes a teammate. Wally hates her also. Annoying her more often and not caring about her. They never say they are "friends" which others agree that they're not, but as teammates or frenemies. No one says that they do like each other or they're just pretending not to.

Bathroom: Wally woke up bright and early to shoot hoops with Robin. He got out of bed and headed for the door. As he opened it he saw Artemis walking to the bathroom and as Artemis saw him, she ran for the door. Wally used his super speed to run inside but Artemis slammed the door shut making him run right into the door. He flew backwards. As he stood up he held onto his pants preventing from wetting himself.
"Arty come on I need to pee!" he begged.
"Pee outside" was all she said. The shower turned on. Wally frowned jumping up and down.
"Please Arty! I really need to!!!"
"Sorry I'm already in nude mode. Go run to a restaurant." she closed the curtains. Wally ran around and around in circles.
"I haven't eaten yet! PLEASE OH PLEASE ARTY!!!" he almost cried but held back the tears.
In the other part of Mount Justice, Robin and Kaldur sat in the kitchen while Megan cooked a meal.
"All in favor of them fighting" Robin sighed. "Again?" he put his hand up followed by Kaldur and Megan.
"I wish they could just be friends. Less arguing, fighting." Kaldur said. Everyone nodded. "What do you thinks going happen?"
"Artemis lets Wally in, he flushes toilet, Artemis gets mad, arrows start flying" Robin was right. A loud scream of frustration echoed in Mount Justice. Wally appeared running but laughing his head off. Artemis on the other hand was chasing after him, a bow and a couple of SHARP arrows with her. She was wearing a green singlet with an arrow on it and a worn pj pants. It only took a couple of minutes for Wally to get about 3 or 4 arrows ( 5-7 if Artemis is real pissed ) on him but Zatanna could do a little healing magic to well, heal him. You can't stop Artemis or else, your dead.

Failsafe: "Got you covered!" Artemis yelled telepathically with 3 arrows laid on her bow. "Get inside! I'm almost there!" she released the arrows and ran toward the bio-ship. Her bows exploded a flying ship, but one crashing to the ground was stable. It began to fire at Artemis.
"Artemis! Behind you!" Megan warned her. Artemis stopped to turn around, her arrow laid on her bow but it was too late. The laser struck her making her disappear in clear sight.
"Artemis!!!!" Megan cried.
"Artemis!" Robin shouted. Kaldur jumped off the bio-ship and took hold of his weapon.
"Get inside all of you" he ran forward and with a slash of his weapon, the ice cracked and water burst up flying the ship in the air. As the ship shot another laser, Kaldur made several spiked ice and blew up the ship. Silence was among the teenagers. Everyone felt such sadness for Artemis except.... Wally. He crossed his arms with no emotion on his face.
"Their dead! Every single alien, if its the last thing I do!" Robin showed such anger and sadness at the same time.
"Is it worth it?" Wally walked inside the bio-ship. No one bothered to answer.
They took lift off and silence went on besides Megan crying and weeping.
"Nah! Ah! Ga uh AH!!!" Robin moaned out hitting the desk several times.
"There will be a time to moan later. Now we have a job to do. Defend the earth and ensure that Artemis's sacrifice was not in-vain."
"Back to the cave?" Megan asked preventing from crying more.
"The Hall of Justice. The human race must know that there are still heroes defending them" as they flew off everyone tried to calm down. "There is still hope" Wally on the other hand was looking at Robin suspiciously.
"Why are you so angry? I mean its not so bad-"
"NOT SO BAD!?!" Robin cried. "That's our teammate! Our friend!-"
"Your friend!" Wally interrupted. "She means nothing to me..." he turned away from Robin just before the others starred in shock.

New Year's Kiss ( Auld Acquaintance S01 ep 26 ):
"Happy New Year, Justice League"
Conner and Megan smiled at each other. As Megan put her arms around him they kissed, it felt so pleasing. Robin stood a few centimeters away from Zatanna smiling at the sight of his teammates. Zatanna pulled him closed (he was surprised by this action) and kissed him. Robin of course kissed back his hands laid on her hips.
"Likin this team more every day" Rocket replied. She put one hand on Kaldur's chin and kissed him. Red Tornado lay on the floor limbless watching the teenagers.
"Human customs still elude me" Wally and Artemis glanced at each other and crossed their arms.
"Don't expect me to kiss him" Artemis said with an annoyed expression.
"What she said" Wally turned away from her. They both walked away in different directions. The teenagers stopped kissing and looked at each other.
"Why can't they just get along like the rest of us?" Robin asked holding Zatanna's hand.
"Well we tried putting them in a room chained together until they worked together, but they escaped. We tried love potions but the magic never lasted. We tried reading their minds if they were just "acting" and liked each other but eventually, no" Conner sighed and starred at the floor.
"Well there's nothing we can do" Robin started to walk off with Zatanna. Others went their separate ways too (not as in leaving the team forever!).

That's just probably just some opinions if they never liked each other. I'll probably write a YJ invasion one but that's if people read this article and comment on it so I know (or be a fan ^.^).
Hope you enjoyed it!