“Imagination will often carry us to worlds that never were, but without it, we go nowhere.” ― Carl Sagan
I've been a player since 2005 and a GM since 2018. Combat and exploration are crucial to a good campaign, however, what turns a good campaign into an amazing campaign, in my opinion, is character growth. Just like in a good book, I want my PCs and NPCs to grow into something more than what they started in, even if the destination is unexpected.
If you like walls of text, you can read how my current campaign is faring here.