shame

i recall an incident few years ago.
i was trying to be nice to this person to gain something from the person.
while i was helping the person on something,
the person asked: why are you so good to me suddenly?
for that second, because i know the reason behind i felt so SHAMEFUL.
but i managed to hide it.
from that moment onwards, i swear to myself i never want to feel that way again.
even when i think of it now,
i wished that it never happen.
but because it happened, i learned shame.
i don't understand why some people can't feel the shame when they are in the same situation.

p/s: tq for teaching me shame.