I'm past my 20s and never read much manga. If you had to pick 3 which I absolutely should read, what would you recommend? I don't have much preference, but I think I'm a little too old for shonen, unless it really holds up if you're way past your teens.
Stuff I read:
JJBA pt.4-5 (dropped on pt. 6, didn't like the characters)
Love Hina (it was alright, got me hooked)
Yotsubato (reading right now, good though very lighthearted )
Dropped: Hokuto no Ken, Black Cat and Gintama, Blame, Slam Dunk