I lolled so hard when I first started my game (when I bought it on release date) and saw Tierno's face when you're getting ready to pick your Pokemon xD They are quite pointless indeed, Trevor wasn't that annoying to me, but kinda bugs me he always kept moaning about his Pokedex. The dance-thing about Tierno kinda irritated me xD and like it was said earlier, surprises me too he didn't even had a Ludicolo on his team (he also reminded me of the Disco Freak Guy, can't remember his name, on Pokemon XD Gale of Darkness who always was dancing and had a whole Pokemon Team consisting of 4 Ludicolos xD). I kept thinking, if you want to keep dancing, why not join the Kimono Dance Theater xD (wait, too fat to fit in a Kimono anyway, so then bug the players in the Kalos Region).
Calem (since I play as a girl) always found a way to show up at the most "no-time-for-rival-battle-even-though-I-always-win" moments in the game that bugs me… My friend was on his way to the Pokemon League, and on that spot in Victory Road he kept losing to Serena 'cause she HAD to battle there >.> Also very frustrating to have healed your team for a gym, going in with a lot of expectations to win, prepare some tactics, NOPE! rival battle spam first xD Aaaand back again to the Pokemon Center it is >_<
Shauna was also kinda annoying for constantly whining about how we grew as a "friend group" and how we somehow managed to have greater bonds blahblah xD And she didn't even believe me when I said I beat Team Flare myself in Lumiose City >.>
And I had a "whaargh!" moment when I FINALLY could go to route 14 to catch a Goomy to complete my team, but NOOOOO we HAD to go to the "erhem Spooky House" first >_> just some homeless guy begging for a tip... 'cause "my dear friends" had to check it out (nope, not Calem, he is too busy catching and training his Pokemon, like I don't want to spend time on that rather than checking out some homeless guy in an old shack xD)
Then last but not least, the most "wtf are you guys doing here moment" was when I beat the League and, yes why the hell not, they too showed up on the stage with me. I was like "wtf you guys, you didn't do anything! >.>" face… (they are just leeching our awesomeness/efforts away from us :x) so why get the credit for it.
Calem/Serena also gets a Masterball (''erhem great help..) when defeating Team Flare at the Pokeball Factory, when later in the game they carelessly leave you behind with like.. wait.. what? 4 members of Team Flare to defeat in like, one time?! >.> what great friends you are… Great job..