The next time someone tells you “don’t be negative”, ask them if they put on a jumper, or turn up the heating, when they feel cold.
If they answer “yes”, or variants thereof – congratulations! They’ve “been negative”!
Feeling “cold” is a negation – it is an absence of warmth. Addressing feeling cold by taking steps to counter it is admitting you don’t like the sensation of being cold – hence, you are “being negative”. (You are “not warm”, and you are voicing that.)
Taoism holds that it is negative emotions that lead to positive ones – it is only through feeling pain that you can work to relieve it.
Imagine all the things that would never have been invented if no one had ever acknowledged being dissatisfied? Aeroplane travel, central heating, electricity, smartphones, computers, cars – the list is endless. The best things come from looking the worst feelings squarely in the face, admitting to them, talking about them, and doing something in response to them.