It also grants them empathy toward others, in a sense that they feel what the other person is feeling unconsciously, and also allows them to see through other's eyes.
If their emotional state is a good one they will do everything better while in that state. It's like mental adrenaline.
It's all relative to the individual as to how sensitive they are, some INFPs may purely go by the person's intent and feel good about that, disregarding if something simply sounded negative.
The Extroverted Intuition of an INFP will be used to make connections between things and to read in between the lines. Ne allows an INFP to see the possibilities of information coming in, allowing them to see how it could change and vary.
Ne also is a great people reading function, with it's use to possibly predict the actions or thoughts of others. Ne is also an INFP's advise function, meaning that they will primarily use Ne to give advice to people or to make suggestions. This makes INFPs and INTPs give off an impression of eccentricy when they are giving advice, since they are thinking of possibilities out of thin air with no real base besides a theory. Even though this is completely natural for them, it will appear that they have a "think outside of the box" attitude to others.
Tertiary- Introverted Sensing/Si: Introverted Sensing is a staple for INFPs. Even though it's tertiary it's usually being put into good use by remembering specific details, and also remembering how things were. When an INFP takes in information, they will process it through their Fi, Ne, and Si. The Si part of an INFP will remember the details about an experience or thing, and relate it to how it was before and will check for changes or inconsistencies. Ne is the fuzzy part of an INFP's perception of the world, and Si is the concrete part of an INFP's perception of the world. An INFP will remember the details of something, and this is put into use especially when making decisions for leisure. How did this make me feel before? What about it made me feel this way? Questions like that will be asked and answered in their heads. If Fi and Ne fail them in a situation then Si will take command, checking for details and linking them to past experiences. Si is the INFP's relief function, meaning that use of this function is generally used for relief and reassurance. With this in mind ISFJs and ISTJs make excellent people to be in an INFP's life, due to their dominant Si.
Extroverted Thinking is a very good tool for INFPs. It allows them to rationalize a situation or a problem of theirs, more often than not resolving the problem whether it's personal or emotional. When everything else fails for an INFP they will resort to Te (if they don't already resort to Te), and they will rationalize their feelings and try to make sense of everything. It's a tool for closure, for inner harmony. Extroverted thinking allows INFPs to see the logical boundries of things and the logical reasons behind why things happen, so if they turn to this then they can eliminate a source of negative feelings from the picture. This can mean asserting your problem toward someone onto the causer of the negative feelings etc.
Te in INFPs is also a tool for debate, for applying logical reasoning to a situation rather than how you feel. If INFPs find a nice balance of this then they will do very well in life.
They will remember random negative emotions from decades ago and will feel them vividly.