O que significa there's no fence, only a gate. dont be sheeple ?

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Basically it means that there are multiple ways to achieve something, and that you shouldn’t only follow what the majority of people do. For example, let’s say you wanted to become wealthy. Most people go to college to try and get a degree so that they can hopefully get higher paying jobs. While there are many alternatives to this, you could become a certified plumber, which requires no degree, and if you work hard you will make a very high amount of money, similar or even greater than many college graduates.

In essence it is expressing “don’t limit yourself to what everyone else does” or “make your own path”.

Hope this helps! Let me know if you’d like any additional clarification.