Let me asking you something: Have you ever had a bad day at work? Has your boss ever treated you unfairly? Have you ever become so frustrated with your job that you begin to question why you put yourself through the stress day in/day out?
I'd say most, if not all of us, have had days like this. It's normal to want to vent your frustrations about your workday.
However, I find it interesting that when actors complain about their work, instead of the "I hear that" type of replies, they're thrown the cliché "Well this is the business" or "If you can't handle it, get out" or "You don't know what stress is yet" or any other proverb that tries to disqualify an actor's frustration because it's the nature of the industry.
Actors are allowed to get stressed with their jobs. Actors are allowed to complain about it. At the end of the day, acting is a job just like any other.
No industry is perfect and it's completely okay to talk about its imperfections. I'm not a mental health professional but I'm going to assume that venting one's frustrations in a healthy way, is a good thing. And just maybe, talking about these issues in the open, can lead to solutions.
But what we need to stop doing is telling actors, and any other entertainment professional, that they just need to "suck it up" because this is the way the business is.
What might come easy to one person, might not to someone else. We need to stop perceiving frustration as weakness and acknowledge that there might be a serious issue which is causing such frustration.
If anything, it would certainly lead to a more supportive working environment. So if things are getting you down, you're angry about how rehearsals are going, the lack of callbacks or stress during hell week - vent away. It doesn't make you less of a performer, designer, director or crew member than anyone else.