One of the challenges of some traders is that they don't know when is the right time to enter the market. Some traders feels when the market is red it is always a wrong time to get into the market to trade. If the green should only be considered as the best time to enter the market, I think it won't always be a right decision.
Not always. Green is the best time but if you can identify the end of red to the beginning of green then you are good to go. The indicator that can determine this I think it is RSI because with RSI you can determine overbought or oversold thereby making your decision. Also you can use MA to support RSI on that.
Going into the market when it is green is just greedy sentiment for trading.
How? When the market is green, that is suppose to be the right time for possible profit if you do your research. What matters is how long the green will last before the red appear. Of course there are different timeframe, 1 minutes, 5 minutes, 15 minutes, 30 minutes, 1 hour, 4 hours, Week and months. So depending on the time you are trading, the longer the time the better the chances.