Anyone could show you how deep DBZ is.
With all it's family bonds, fighting and sacraficing to protect the greater good...
It also emphasises life lessons like not to waste time on what you could do now (i.e. throw that spirit bomb now, not later).
Finally, before even TTGL came along it exemplified the new replacing the old, as seen by Gohan taking over for Goku. The newest generation shall be the strongest... The old will eventually be reincarted 50 odd times but mostly be forgotten if you don't consider DBGT cannon.