Superhuman. It's the only software I use at work that I pay for myself because it makes dealing with email so much less painful. To the point that it's actually

Superhuman. It's the only software I use at work that I pay for myself because it makes dealing with email so much less painful. To the point that it's actually almost enjoyable clearing out my inbox. The ability to do absolutely everything from the keyboard and being so responsive really makes a huge difference.