You should never dismiss a metaphor just because it's 'meaningless' - analogies help us to put all sorts of things into perspective, and when you take your example from a rational world like those of maths and science, it can help you to tackle the more irrational challenges you face, such as your inner demons and emotions.
Take the example of 'positivity', for instance - in terms of emotion, it's quite an abstract concept, and you might not be certain of whether you mean 'positive action' and being proactive about your problems, or 'positive thinking' and simply hoping that they will somehow be resolved.
Either can be helpful, letting you think more positively about a situation that's out of your control, or encouraging you to take even difficult actions to resolve a problem that's still within reach.
But in science, particularly Physics, there are very specific definitions of positive and negative, and of neutral too.
Positive Fundamentals
In an atom, for instance, there are positively charged protons, neutral neutrons, and negatively charged electrons.
And y'know what? Those negative particles are TINY compared to the others - roughly 5.5 x 10-4 units, where one unit is the mass of a proton or neutron.
That means you need almost 2,000 electrons to equal the mass of a single positively charged proton.
What's more, those negatively charged electrons are held in place by the positive charge of the protons, orbiting the heart of an atom just as the Earth orbits around the Sun, and equally powerless to break free.
In fact, electrons are so 'insignificant' that they don't contribute towards the atomic number OR the mass number of an element on the Periodic Table.
You might begin to think that negativity doesn't really have much of a place in the universe...
Forces of Attraction
But wait, what about magnetism, right? The attraction between opposite forces that keeps those electrons in orbit, and inherently binds positivity and negativity together in an uneasy partnership?
Well it turns out there's an even stronger force that binds positive and neutral particles together - so strong, in fact, that its name is simply the Strong Force (or the 'residual strong force' when you're talking specifically about protons and neutrons).
It's been around since the beginning of Time, it's the strongest force there is, and it doesn't give a damn about negativity - it's 137 times stronger than the electromagnetic force that holds opposite charges together.
So the next time you're feeling down, remind yourself that negativity is WEAK and positivity is STRONG - and that the strong force, which holds positivity at the heart of every atom in the Universe, has itself existed FOREVER, and always will.