If it's not okay in a vacuum but you justify it when someone does something bad to you first, be careful that, if you're wrong about what the other person did, you're not doing something abhorrent.
https://yourmeaninginlife.com/blog/sacrificing-your-ethics-for-your-ethics
You can always find a reason to complain, and you can always find a reason to be grateful. The former will lead to a miserable life; the latter will lead to a more pleasant life.
https://yourmeaninginlife.com/blog/it-will-always-be-something
There are many misconceptions about how important growth is to your life, from what kinds of growth are possible, whose growth is meaningful, and how growth is meaningful even in the face of endings and death.
https://yourmeaninginlife.com/blog/misconceptions-about-growth-oriented-meaning