Could be quite a few different combination of things I guess. Having dealt with certain things in life in the past could give you a better perception of when others are going through the same. Learning about something and having a deep understanding of it or of the situations that lead up to said event/happening that makes you more aware of it when its about to go down.
Culture, drugs, libido, intelligence, education, sense organs, emotions, chemical imbalances, experiences, religion, upbringing, light, political persuasion, language, media, and situation.
Real life experiences. Can't deny that at times the past can also add to it; sometimes a moving book and an intellectual input shared by someone significant/special. Things that have impact straight to the thoughts that remain there. Memories....
Rhetorical devices such as euphemisms (a neutral or positive expression only to avoid negative associations), dysphemisms (produces negative effects in order to change one's outlook), weaselers (watering down or weakening a suggestion to protect it from criticism), downplaying (an attempt to make someone or something less significant), sarcasm, hyperbole (an extravagant overstatement, which can also be used in ridicule), proof surrogate (an expression to suggest something is true without displaying evidence of its claim), apple polishing (ass-kissing without genuine intentions).
Many of these methods and tactics are used throughout political campaigns, product advertisement, commercials, etc... in order to dilute one's perception. I hope that this helps. PM me if you require any more suggestions.