Another beautifully designed piece of Emacs software is magit, where the defaults are extremely sane. The package is self-documented and you can learn it all by typing ? anytime. Being able to git log the file you are in is also a huge plus.
People say org is the killer app, but imo it has nothing on magit. (It's a weird comparison Ill give you that)
I'm thinking of donating again
For instance interactive rebaseing is so much better in Magit.
Magit forces certain workflows because the author and community feel those work best, and stepping outside of that is often an exercise in frustration because you're not doing things "the Magit way". After going through a few issues on their tracker it was clear that there's no place for improvement suggestions unless it aligns perfectly with the maintainers' vision.
It feels very "holier than thou" and the constant hype around it everywhere is a bit off putting. Maybe it's just me, but I prefer using plain Git in a regular shell (Emacs shells are also unusable for me), with shell and Git aliases, and helper tools like scmpuff[1].