What does 'get knocked about' mean?

Question

What does 'get knocked about' mean? I referred to some dictionaries, but I couldn't find any definition that fits the context.

We all have set patterns in life. We like to label ourselves as this or that and are quite proud of our opinions and beliefs. We all like to read a particular newspaper, watch the same sorts of TV programmes or movies, go to the same sort of shops every time, eat the sort of food that suits us, and wear the same type of clothes. And all this is fine. But if we cut ourselves off from all other possibilities, we become boring, rigid, hardened―and thus likely to get knocked about a bit.

The Rules of Life: A personal code for living a better, happier, more ...

Answer 1

knock about
in American English

or knock around
Informal

1. to wander about; roam
2. to treat roughly

Collins Dictionary

In this case, it's the second definition, and since your example uses "get knocked around" instead of "knocked around," it means to be treated roughly.

In context, "If we cut ourselves off from all other possibilities, we become boring, rigid, hardened...and thus likely [to be treated roughly by life]"

This doesn't make very much sense if you don't read the preceding paragraph. Why would being boring mean life is going to treat you roughly? In the previous paragraph, the author writes, "Flexible thinking is a bit like mental martial arts - being ready to duck and weave, dodge and flow."

So, the metaphor is: life is going to attempt to strike you. If you are rigid, you will get hit. If you are flexible, you can avoid being struck.