Humans see mud and soil as dirty but earthworms and other mud
creatures see mud and soil as home. Humans see shit and toilets are
dirty but there are worms which like these places so much and see
them as home. Sorry eh, very disgusting right. What I'm going to
say is what we perceive depends on our karma.
Humans see water as water, ghosts see water as blood, heavenly
beings see water as crystal, fishes see water as homes and to leave
it is equal to death.
Buddhas see samsara as sufferings but humans see samsara as home
and attach to it, so ignorant that many refuse to leave. I guess it
is just like we wonder why earthworms like to be in the soil and
mud.
There is a Buddhist saying "众生原本一种性，只是业缘别形体"。It means we are all
the same, the difference is our karma that makes us different in
appearance. Due to different karma, we are born in
different realms (animals, ghosts,hell, demi-god, heaven and
humans). Humans are born in different countries and within
the same country, different families (rich or poor etc.)
Some people do not have a chance to listen to the Dharma or have
a chance of knowing the Dharma but do not believe it, this is
also due to their karma.To have a chance to know and believe the
Dharma are those with deep 善根, so cherish it.