Why is Mercury always observed quite close to the horizon when it features in these pairings?

Answer

Its orbit keeps it near the Sun

Mercury's orbital mechanics dictate that it is always seen relatively close to the horizon because its path around the Sun keeps it near the Sun's apparent position in the sky.

Why is Mercury always observed quite close to the horizon when it features in these pairings?

#Videos

Venus reaches its greatest brightness near the Moon (21 to 27 April)

astronomystarMooncelestial bodybright object