Four fixed signs, and nobody moving
Taurus, Scorpio, Leo and Aquarius are the four fixed signs, one to each element, and they occupy the middle of their seasons. Everything difficult that is said about these combinations comes back to a single property: fixed signs do not concede on request, and when two of them disagree the disagreement has no natural end point.
That is the honest content of the Taurus warning list. It is not that these people dislike each other; it is that the same conversation can run for years without either party updating their position.
The angles, stated plainly
Scorpio lies 180 degrees from Taurus. Leo and Aquarius lie 90 degrees away, one on either side. Those are the only hard angles Taurus makes, so the difficult-signs list has three entries by arithmetic rather than by judgement.
Taurus and Scorpio is the axis of what is mine against what is shared, which is why the old texts read it as a question about resources and trust rather than as an incompatibility. Leo and Aquarius square it from the fire and air sides, and in each case the argument is about whether value is demonstrated or simply held.
Venus and Mars are the planets doing the work
Taurus is a Venus sign and Scorpio is a Mars sign in the classical scheme, so the opposition is really Venus against Mars, want against pursuit. Read that way it is obviously not a warning. It is the standard description of attraction, which is exactly why the Taurus and Scorpio axis appears so often in long marriages as well as in cautionary articles.
The useful version of the question is where Venus and Mars actually fall in the two charts, and how close the angle between them is. That is measurable and it does not depend on the sun signs at all.
What genuinely makes a comparison heavy
Strain in a chart comparison appears in contacts between personal points. Saturn from one chart sitting on the other's Moon or Venus is the classic weight, felt as duty where affection was expected. Neptune on a personal planet obscures rather than opposes. Close Mars-to-Mars contacts describe the speed at which a quarrel becomes loud.
None of that can be inferred from two birthdays, and the width of an aspect matters enormously: an angle within a degree behaves nothing like one eight degrees wide, and lists have no way to distinguish them. The synastry calculator measures the real angles from two birth times, and synastry explains what is weighed.
Better than a ranking
The Taurus and Aquarius page describes what the two hold in common, where the deadlock forms and what fixity does to both of them. Read that instead of noting a position on a list.
If both birth times are available the charts settle the matter far better than the sun signs can.
Questions people ask about this
Which signs are named difficult for Taurus?
Scorpio opposite, Leo and Aquarius square. All three are fixed signs, which is the real source of the friction described.
Is Scorpio a bad match for Taurus?
The geometry does not say so. The axis is classically Venus against Mars, which is a description of attraction as much as of conflict.
What makes fixed-sign disagreements different?
Neither party concedes on schedule, so the same subject recurs rather than resolving.
What predicts real difficulty?
Saturn and Neptune contacts to the other person's personal planets, close Mars contacts, and tight orbs.