What an Idiot!/Western Animation/Ben 10

Ben 10

 * "Back With a Vengeance", Ben and Gwen are trying to escape the Null Void, a horrific pocket dimension. However Ben's arch-nemesis Kevin is trying to escape before them. Then Ben calls to him, saying "I'm over here Kevin! Come get me!"
 * You'd Expect: Kevin to do, as he said a few minutes ago, "leave him stranded in the dimension with his arch nemesis, which is a satisfying enough revenge.
 * Instead: He charges at Ben to kill him. A head hop and a few jumps later, Ben is home free. Kevin is just plain screwed.
 * "The Galactic Enforcers", Ben and the titular Galactic Enforcers are fighting two crazed and deadly mercenaries called Sixsix and Volcanus. Gwen and Grandpa Max are locked in the Galactic Enforcers' ship, being not allowed by the Enforcers to be involved with the business below.
 * You'd Expect: Gwen and Max to stay where they are. They are both unarmed humans and Max doesn't even have access to his Plumber equipment. They are not going to be able to dent the two villains in the state they are in now.
 * Instead: Max hacks and activates the teleporters and he and Gwen teleport, Leeroy Jenkins style, down to the location. Upon arrival, they IMMEDIATELY get in trouble and Ben has to save them, allowing Sixsix and Volcanus to get away with what they wanted.

Ben 10: Ultimate Alien

 * Darkstar manages to find a way to Ledgerdomain, a realm made of mana that can feed his need for energy. While there, he meets Charmcaster, who rules said realm and controls its power. Despite having a somewhat insane sense of fun, she is completely smitten with him. Hell, it is all but stated outright that she slept with him. In addition to that, she's willing to give him however much energy he needs to destroy his enemies.
 * You'd Expect: Darkstar to realize he's hit the motherload, and not do anything to betray the trust she's put in him.
 * Instead: Complete sociopath that he is, Darkstar not only persists in acting like she owes him more, but practically ignores her entirely. He boasts about taking over Earth and her dimension and continues to lust after Gwen (who, remember, wants nothing to do with him). Predictably, she depowers him then tosses him back to Earth like garbage.
 * For added stupidity: The above mistakes weren't actually enough to completely alienate her. All he had to do was remember her real name: Hope. Just one simple little name. He can't even do that!

Ben 10: Alien Force

 * "Kevin's Big Score" - Kevin finds out an old partner of his in the blackmarket alien tech underworld has a Holoviewer containing a message for Ben from his grandfather.
 * You'd expect: Kevin to share this information with Ben and Gwen so they could come up with a plan to buy, trade for or steal it.
 * Instead: Kevin steals the Rust Bucket to trade it because he doesn't want to bring up his past - a past Ben and Gwen already know about! - for fear they wouldn't trust him again. But stealing their grandpa's house with no explanation is sure to gain their trust...
 * "Above and Beyond" - Alan comes up with an idea, but before saying what it is, believes it to be stupid. Pierce, as the auxiliary leader of the group, asks for the suggestion anyway, and it turns out to be to use the Plumber's Badge locator feature to find Grandpa Max, who is clearly trying to hide from Ben.
 * You'd Expect: Pierce to realize from Alan's questioning of his own suggestion that Ben may be using the locator himself to make it easier for himself to find Max. If he is to use the locator, it would be better to do so to keep track of Ben's location and work off of that.
 * Instead: He just goes along with the suggestion without second thought or any other sign of major caution. He gets separated from Alan and falls into a trap where he is isolated against Ben. Cue being on the rough end of a Curb Stomp Battle as a reward for disappointing sense for a leader.