外行看热闹，内行看门道

外行看热闹，内行看门道:

Literally means:

connoisseurs appraise and appreciate whereas laymen stay and watch the fun in the crowd

Actually means:

外行, layman, is a person knows little about or has no experience in a certain field. 内行, refers to professional. 门道 is the know-how or technique.

This phrase means a non-professional tends to be misled by the fancy forms, and he can only see the appearances of something; whereas a professional can see through its appearances and catch its essence.

It usually connotes that laymen and professionals usually look at the same thing from different angles, thus having different results.

外行，不懂行的人，即对某项专业或某项工作不懂或没有经验的人。内行，懂行的专业人员。门道，事情的原理或道理。

外行看热闹，内行看门道，不懂行的人为形式上的热闹所迷惑，只能看到表面的东西，而懂行的人则一眼就可以看到实质。

多用来指外行和内行看问题的角度不同，效果也不一样。