Execution time (instant in demo, not in real), slippage, price feed (the price shown in demo could be different from the real price)...
No. That is not correct. Because the strategies i have played on demo given same results in real also. 😎
The feeling of trading your strategy shouldn't change whether on demo or real when you are really ready ( you know how to handle your winners just as you do with your losers. )
Demo and Real Performance matching is only possible when the strategies do not exploit the vulnerabilities within the trading platform and server infrastructure.