Most of the time the misleading is not coming from the others, it is coming from ourselves.
For example, when we saw a glass has a liquid inside, if it is transparent, then we would assume that it is a glass of water or wine especially it accompanied with a meal on the dinning table.
If we put several glasses with different transparent liquid inside, such as water, wine, beech, gasoline, soft drink and etc, if we just use our observe to determine which glass contain the water, it is close to impossible. Either we can use our different organs of our body to test it or use the tools and chemistry theory to analysis it to figure it out one by one.
Once the glass contain the gasoline before, you continue to use it to contain water without washing, the water still have the gasoline smell and its remainders. When you drink this glass of water, you will not find the real taste of water.
The same theory I put it in learning Feng Shui, once your mind is poisoned by other masters or focused on your bias to analysis, although the truth or fact is in front of you, you will never admit, it is because you are not cleanly washing your brain before you listen to me.