This remedy is curious because its name reflects its healing quality. It's a very useful essence for those who get impatient when things aren't moving fast enough for them. This might be when the person they are dealing with isn't as quick thinking, or as fast as them, or perhaps when travelling to somewhere and caught in a traffic jam.
The impatient state is borne of fear, especially when you feel that you will miss out on something by being slow.
This could include:
Getting into trouble for something not finished on time.
Awaiting medical treatment in an emergency
Having limited energy reserves, hence not wasting precious time and energy.
I find that Aspen (for undefined fears) compliments this remedy nicely, as often you may become impatient due to a fear that you should be somewhere else or you might miss out on something. (Of course, if you know the reason, then Mimulus would be the better remedy.)
In regards to this, it's worth noting that some remedies will only bring temporary relief if the primary cause of the feeling isn't dealt with. Hence, if fear is causing you to be impatient, taking the appropriate remedy for fear may also take care of the secondary cause.
This is a good remedy for when you fear the future or that life is going to try and screw you. Taking it can bring much reassurance.
For Empaths:
Empaths may find this useful as they often find many aspects of their life dreary. For many such empaths, the mental stimulus of small talk just isn't enough for them. They will tap their foot impatiently while enduring the minor details that others are fascinated by.