Impatience is the tendency to be irritable or easily frustrated. A bus driver's impatience often results in her yelling, honking her horn, and gesturing angrily at other drivers.
If you are easily annoyed or provoked, your impatience is showing. Impatience is also why you hate being late, or having to wait for something or someone. It comes from patience, the habit or trait of being able to wait calmly or even tolerate discomfort without complaining. The "opposite of" prefix im- tells you that impatience is the complete opposite.