Fantastische Hure said:
I'd still consider that selfish on Goku's part considering he likes to fight stronger characters. That's been a trait of his.
So do the majority of martial artists in the main cast, yet Goku doesn't make it his ultimate factor in decisions like Super loves to portray him as. His most selfish action in the Cell Arc indeed stems from this, admitting he wants to fight the Artificial Humans rather than kill Gero beforehand, but he also adds that Gero has yet to do anything wrong. This makes his reasoning a bit more complex than just wanting to fight, and the same goes for training Oob. It is part of the reason for his action, but it's more of a 50-50 split than 100% selfishness.
Him not defeating but is more selfish in my opinion. There's also that he could have easily defeated Boo and then just taught the next generation how to defend the earth if the need arises any-time after, why do it in a do or die situation? Especially considering fusion can be taught at any-time without taking a-lot of time.
I'd say it's inaccurate to say it's selfish as it's more so reckless, which is indeed true. However, he did rationalise it by specifying he wanted the new generation to take care of themselves. On top of that, it didn't seem as though he could obliterate Boo at any time he wanted during their fight. If he did destroy Boo, it would likely take more time and use up all the time he had on Earth, meaning he wouldn't be able to teach the kids fusion. His goal was to be a distraction for Boo whilst Trunks got the radar and he didn't want to waste what little time he had.
Talking about recklessness, Future Gohan is also guilty of this in going to face #17 and #18 2 on 1 believing he could win. It wasn't just bluster either, considering he was genuinely shocked at the idea of #17 having shown less than 50% up to that point. That said, he was reckless in going to attack on his own without being at a level he could handily dispose of the two from his prior experiences, which certainly wasn't so when he presented doubts at his survival. That's not a flaw in his character writing, but it does go against the idea there's a vast difference in character between he and his father.
More to the original point, Gohan pretty much beats the audience over the head on how much he's trying to emulate Goku with talking about how much his father inspired him. Compare this to present Gohan's treatment of both his father and Piccolo, he loves the former and respects the latter enough to dress like him as future Gohan does for Goku, yet at the end of the day he still has his own motivations and a thought process different from them (also it's debatable whether or not Gohan has some level of Stockholm Syndrome for Piccolo from his experiences in the Saiyan Arc, but that's a rabbit hole for another time). Meanwhile, we don't get enough time to see Gohan's defining character traits stand out in his future self. We do see him taking an approach to training Trunks somewhat inspired by Piccolo's teachings, but that's about it.