Throughout Dragon Ball Z, Goku fights an ever-increasing roster of antagonists. These enemies always escalate the stakes and are much more powerful than those before. When Goku faces off against these opponents, he always rises to the occasion and learns a new technique or gains a powerup that wins him victory. Out of all these abilities and transformations, Instant Transmission is definitely the most useful.
After Goku defeated Frieza on Namek, he found himself on Planet Yardrat. The aliens there welcomed Goku and taught him how to perform the Instant Transmission technique. This ability allows Goku to instantly teleport anywhere he desires, regardless of the distance or if the location is in another plane of existence. Goku has teleported to different planets light-years away and even to Otherworld. This technique is so powerful that it begs the question, "Why doesn't Goku use the technique to its full potential?"
Why Didn't Goku Prevent the Resurrection of Buu?
During the Majin Buu Saga of Dragon Ball Z, an evil wizard named Babidi attempts to revive the powerful demon Majin Buu. Goku and his friends track Babidi to his spaceship buried underground. The group fights their way through rooms of Babidi's minions, attempting to stop the wizard before the resurrection is complete. Ultimately, the group fails to prevent Buu's resurrection.
While fighting in the spaceship, neither Goku nor anyone else in the group suggests simply teleporting directly to Babidi and stopping the wizard immediately. This is definitely something that's within Goku's abilities. Teleporting immediately to Babidi and defeating the much weaker wizard would have been the easiest and safest route to take. Instead, they chose to waste time by fighting minions.
So why didn't Goku take the most direct path that put both him and the planet in the least amount of danger? It's possible that Babidi and his right-hand minion Dabura were suppressing their ki signature while attempting to resurrect Majin Buu. In order to use Instant Transmission, Goku needs to be able to lock on to the ki signature of a creature near where he wants to teleport. If Goku could not sense Babidi or Dabura's ki while they were at the bottom of the ship, he wouldn't have been able to teleport there even if he knew the location.
Goku Didn't Take the Situation Seriously
Goku's inability to lock on to Babidi's ki signature is the simplest answer to why he didn't teleport to them, but there may be another answer that's even more likely. Goku and the rest of the group that went to stop Babidi didn't take the threat seriously. While going through the different rooms of the spaceship, the group never encountered opponents that pushed them to their limits.
Goku, Vegeta and Gohan easily defeat each of Babidi's minions with little effort. The three fighters even have a game of Rock, Paper, Scissors to see who will get to fight next. Only Dabura is able to pose a challenge, and even he can only stall against Gohan during their fight.
It's possible that Goku saw how weak Babidi's minions were and didn't feel the need to quickly end things by teleporting. The three Saiyans were more than happy to take their time fighting each minion one on one as they progressed through the ship level by level. This wouldn't be the first time Goku seriously underestimated a threat.
Goku Always Prioritizes a Good Fight
Goku has an unfortunate history of letting his enemies get stronger so they'll be more fun to fight. Regardless of the danger that this puts both himself and the universe in, Goku will always choose a good fight over ending an opponent quickly. In almost every arc of Dragon Ball Z, there is an instance of Goku making the wrong choice and it coming back to bite him.
When Vegeta was defeated on Earth, Goku begged his friends to spare Vegeta so that he could fight him later. Vegeta attacked them later while they were on Namek. Goku tried to spare Frieza after the tyrant killed his best friend. Frieza then attempted to strike Goku while his back was turned. When Goku was warned by Future Trunks about the android attack that was going to happen in a few years, Goku decided to wait for the attack instead of acting immediately to prevent it. Most infamously, Goku gave Cell a Senzu Bean, which healed him when he was about to fight his son to the death.
Goku repeatedly makes the wrong choices when dealing with his enemies. He spares them, allows them to power up and even heals them just so he can get the chance to fight them at their strongest. Goku deciding not to use Instant Transmission to quickly stop Babidi and Dabura is likely just another example of him picking a fun fight over the safety of the world.
