Many of us act as if we're in rudderless boats drifting in the sea of life

这句话是什么意思？
We arrive wherever the current and tides take us.It doesn't have to be that way.You see,the boat we are in has a rudder!
还有后面几句

Many of us act as if we're in rudderless boats drifting in the sea of life 急!!!请问most of us可否说成many of us或much of us? I have my complaints like many of us do many .many of用法 100. How many of us ________, say, a meeting that is act of foreign enemies All of us Most of us Some of us A few of us None of us most of the media in the US is owned by only 5 companies,why does this worry many people? all of us 与 of us all many of 的问题