What difference does this make?
Firstly, I like a bit of colour in my life.
More pertinently, using colour allows me to see the relative priority of tasks. This, in turn, reduces my tendency to selectively avoid specific tasks.
At the moment I use four symbols:
This is my MIT – most important task. there can only be one MIT on my to-do list.
This indicates a deadline or someone is waiting/depending on me to complete this task.
This is for all other tasks.
This is my favourite symbol. I don’t think I relly need to explain why!