Tiger and Snake.
Harm
A quieter strain: small misreadings that repeat. On the wheel the two signs sit 3 places apart.
The six harms are pairs where each sign interrupts a combination the other would otherwise make. In practice it reads as small, repeated misunderstandings rather than open conflict.
Named early, a harm pairing is manageable. The fix is usually saying the obvious thing out loud, because each person tends to assume the other already knows.
Beyond the year sign
We compared 200 Tiger and Snake birthday pairs born between 1950 and 2005. The year sign changed little across those readings. Even classical clashes covered nearly the same range as harmonies.
The deeper charts varied much more. One person's nature could support, restrain, or closely resemble the other's. The year sign sets a tone. The two exact birthdays decide the pair.
What this leaves out
The year animal is one of eight characters in a Chinese chart. The day pillar says more about a person than the year, and a full reading compares all of them. The year also turns at Start of Spring, around 4 February, not 1 January, so people born in January or early February usually belong to the previous year's sign.