As we can see there are more and more casino house being open both online and land base operations, meaning that it's the operators that earning compared to those gamblers who can manage to win, though it's not a surprise that there are lukcy gamblers who can takeaway some portions of those earnings, but the numbers are far smaller than those who lose their money from the day to day sessions.
And like what you said, if you want to have lesser to no stress better to use allocated amount and don't be dominated by your emotions.
This amount is not intended to be lost and be calm, any loss will cause disappointment, even a small budget. You can avoid stress if you play only part of this budget and the stakes are so insignificant that the stake will not affect your emotions. All other situations will cause stress, this is inevitable for every player. Maybe there are those who are so emotionally stable that they will not pay attention to losses, but for this you need to have a special attitude to money, and basically people are careful with it, because they know how hard this money is to earn.