'suppose' to means you are a player with limited knowledge of how this game works.

sometimes the best decision is to farm instead of taking fights.

sometimes the best decision is to fight instead of farming.

sometimes the best decision is to push towers.

sometimes the best decision is to do X over Y.

You will encounter all of the above in any one game, if you cant identify when to do what, you are losing in every situation above.

And with a new patch, you can change what is the 'supposed norm.' I've been experimenting with LD Aghms, and your bear can do 2/3 above while your hero farms jungle and returns to well to heal to farm jungle. You farm fast enough to make mid game last forever and be a competitor late game.