Well, first of all, demo isn’t live trading. When you trade real money, your attitude changes because it’s all in the brain - loss avoidance and reward mechanism (read some psychology behind traders?behaviors/decision making).
To me it seems conniving because it’s subtle, you don’t notice it at the start - you’re seeing only the result or when things have already accumulated. Like at the beginning, you enter a bit too early or you exit a bit too late…you see? It’s tiny shift, and it gets unnoticed because you’re like “I’m in control, all solid.?Or you just are not sure about a potentially good setup. And then all that gets accumulated with time and reaches its critical mass - the pattern has been formed.
Demo has no urgency, and live gives attachment to trade outcomes.
What helped me is I trade very small, so a potential outcome is insignificant hence I’m not attached to that. And I forgot about my pnl. I just ask myself if I followed my rule(s). You can even compare yourself being in this mode for like a week or 2 and then concluding if you stayed within the set limits.That’s it. Hope it helps...