 If you liked Slam Dunk |  ...then you might like GTO |
Apart from GTO being my most favourite of all time, I'm really recommending this because of their similar personality, they're both dumb as fuck, gets rejected as fuck but strong as fuck and real as fuck. The only thing different is plot slam dunk about basketball to impress a girl while gto is a gangster becoming a teacher but not teaching normally the premise revolves around him teaching real life lessons but through the most outrageous way possible. DON'T LET THE IDEA OF A TEACHER PUT YOU OFF THE MANGA i done this so I didn't read for about two years until read it
They're much on the same "yanki school gag humor" vibe. Sakuragi and Onizuka are the kings of funny faces. Both are completely stupid and have very little respect for authority. Their role as characters is to constantly challenge the status quo. Both manga also have their moments of seriousness.