Question

What is the most significant danger of a phishing email?

Answer 1

Phishing email is an email fraud method in which the attacker or hacker send an email which appears to come from well know and trustworthy websites or persons. 
The most significant danger is that email appear to come from a very official company or websites. And it is very easy to be fooled and providing personal information like credit card numbers etc.

Answer 2

I believe the answer is: It can provide access to a computer or computer network

When they gained access to your computer network, it become very easy for the creators of the phising emails to obtain various form of private information from you, such as your social security number, credit card number, email passwords, etc. This expose you to a really high risk of identity theft that could ruin your life.