I haven't used the macOS for a while now, but when I used it here's some things I did.
Get a browser that's not Safari. Chrome or Firefox are great.
I used Adium instant messenger. Same thing as Gaim/Pidgin on Windows. It's much better than iChat.
I had growl notifications installed for a centralized notification system for all my non-mac programs
I had the X11 environment and all the linux base system installed so I could run linux programs along with the fink package manager.
This whole thing tied it in nicely to growl notifications. I also installed developer tools (which used to come on the extras CD, not sure these days). That installs all the programming libraries and stuff.
As I think of more weird stuff I did to my mac I'll post it up, it's been years since I used macOS as my main system.