In one bonus storyline in Dragon Universe, Vegeta goes behind a bush so he can do a Fusion Dance with Goku without being seen "dancing around like a fool." Goku mistakes him for... taking care of business.
Goku: Well, when you've got to go, you've got to go.
Saiyaman...justSaiyaman. His ultimate is merely him introducing himself and pulling off a pose! Do it right and he gets an attack boost. Screw it up and he looks ever so stupid.
The What If? in the first game where Cell accidentally absorbs Krillin. Made even funnier by the fact that his is the onlyWhat If? where the villain loses. And then it turns out it was just a nightmare Perfect Cell was having during the 10 day Cell Game waiting period.
Yamcha goes up against Cell after he's been weakened by absorbing Krillin... and stillloses.
One small one in Frieza's What If? after killing Goku. He's standing there panting...and then merely grins and "Hmph!"'s...and then you notice he had a tooth knocked out.
Goten's winpose after beating Videl. He looks so adorably concerned that Gohan'll be angry at him.
The way some pre-fight dialogue can match up even if the characters don't have special intros. case in point...
Majin Buu: Do you like chocolate? or Yamcha: Think you can handle this?
Kid/Teen Gohan: I'll give it a try!
Some of the special intros, especially...
Goten: (dancing around) Shenron, I want candy!
Omega Shenron: (Folding arms, not amused.) I don't grant wishes for candy!
On the subject of failed attacks, if you fail Yamcha's Spirit Ball attack, his opponent will dodge every hit, then the Spirit Ball will outright spike the poor desert bandit in the face.
Hercule is just as much as a hoot in the Budokai games as in the anime: the first two games turn his giving a bomb-laden handheld video game (as seen in the Buu saga) into one of his Ultimates, while the third adds to his repertoire an attack where, after beating his opponent, he quickly sets up a camera and takes a picture of himself standing victoriously over his foe (complete with him stomping on his opponent as they try to get back up).
"Risking It All For A Friend" can be applied to every character in Burst Limit, meaning you get such iconic moments as Goku being saved by Broly.
Super Buu in Budokai 2 has Absorbtion as his ultimate, where he absorbs characters like Gotenks but also characters like Cell and Frieza. But he can also absorb Yamcha and Tien and it shows him wearing Tien's vest and having Yamcha's scar and letting out a Big "NO!" when he realizes who he's absorbed.
And if you look in practice mode when you do it, you'll see that Buu's power decreases (instead of increasing when he does other characters) when he absorbs the two.
Cell: doing Spirit Bomb ultimate Ok planet, give me that stupid energy!
Alternatively, if you use the Spirit Bomb in the first Budokai Game: