Goku cheated because...

[Fantastische Hure]

...he didn't want to look like a fool in-front of everyone, by having that fugly ridiculous hair having, no eye-brow Super-Saiyan 3 transformation losing to Super-Saiyan 2 Trunks who still looked kewl with the kewl Super-Saiyan 2 transformation but powered-up just as-much as Goku did in his stupid Super-Saiyan 3 transformation. Not to mention that he bragged about Super-Saiyan 3 just a second before.

Even Vegeta called Goku out on it.

What a loser.

 

[Void]

Goku always cheats. Look at his fight with Caulifa and Kale... He said he didn't have the stamina to use SS3 and then promptly turns SSG.

 

[Fantastische Hure]

Goku always cheats. Look at his fight with Caulifa and Kale... He said he didn't have the stamina to use SS3 and then promptly turns SSG.

Goku is the biggest cheater in the series. Adult Goku post-Cell Saga that is.

 

[Animelover5487]

Goku always cheats. Look at his fight with Caulifa and Kale... He said he didn't have the stamina to use SS3 and then promptly turns SSG.

SSG is less draining than SS3.

 

[Flame]

Goku's always been a cheater man. He tried to poke Jackie Chun in the eyes and he used Roshi's sunglasses (outside tools) in two tournaments. He probably kicked someone in the groin at one point too. Heaven forbid someone trying to cheat against Goku or try to poke his eyes out, "That's not fair!".

 

[Jeff Styles]

Goku also cheated in the first round of the 21st Budokai. He use Kinto'un to avoid being thrown out of the ring.

 

[Fantastische Hure]

Goku also cheated in the first round of the 21st Budokai. He use Kinto'un to avoid being thrown out of the ring.

And later when his tail grew-back he just used that as a helicopter in the finals.

 

[Captain Cadaver]

Goku is the biggest cheater in the series.

Pre-Knocked Up Bulma disagrees.