I don't think he meant you don't have to take your responsibilities, promises, work, etc. seriously. He didn't mean that it's OK to live life with no integrity.

我想他并非说你不必认真承担责任、工作和对待承诺等，也不是说可以做不正直的人。

youdao

For example, ultra-poor English I test once passed four, skipping school dormitory only pick 40 people, but also picked to my... so, I will accept all of life to me, good or bad, I have too seriously!

譬如，英语超差的我，考一次就过了4级，搬宿舍全校只挑40人，还能挑到我……所以，我还是会接受生活给我的一切，好，不好，我都认真的过！

youdao

If I have learned one thing it's that life is to short to take things to seriously and that you have to take life for advantage to be happy in a way.

如果我已经学会了一件事，那就是一生中认真的做一件事情太短，而且不得不以一种方式使自己幸福。

youdao

"I am afraid my ability to keep a reasonable house, to meet friends, to have a normal life - that, I think, will be seriously curtailed or stopped altogether", she told me.

BBC: North/South spending divide in social care