Why are mornings sometimes difficult?

It's because mornings put a lot of pressure on us to do whatever must be done to get the day started: In a short amount of time we must finish getting all the sleep we can, get cleaned, get ready/dressed, eat breakfast, arrive someplace at a very specific time, etc. The pressure causes us to become stressed, which results in a hectic and difficult vibe. Also, the average person doesn't get enough sleep at night, and that usually results in morning fatigue, apathy and negativity.