自行其是

I couldn't see the point of letting him have it his own way.

我不明白让他自行有什么道理。

You’re a maverick and you’ll try anything.

你个爱自行的人, 样样要尝试一下。

The committee was doing well until the chairman's independent action gummed up the work.

委员会的工作原进展得很顺利, 后主席自行, 弄糟了。