I wrote of updating my system to include the usage of Tmux. So far, it's going great. I love it and the new additions have been wonderful to work with.
The next best thing that I've change is using yellow more predominantly throughout my interface. I love yellow. Yellow is a great colour. I've made the colour of my system name and the colour of my active tab borders and active window colours. It looks beautiful. Most of the themes I use are dark and the yellow offsets that wonderfully.
Fiery colours are the best overall. I've always loved them. Yellow, red, orange. Sunsets, lava, phoenixes, flames, sparks and much more. What's not to love?
The reason I prefer yellow or all the fiery colours is the brightness. Fiery scenarios can be dark - as I've mentioned; flames, volcanoes, sparks, all things that can be associated with devastation. Yellow is more vibrate. You think of the sun, shining through your window. You think of flowers, gold, lemons, Pikachu (wait, who snuck that cutie in there?). I also think of Link and Zelda embracing after battle with Hyrule Castle in the background. That last one might be because that's my desktop background right now...