Why do we, as humans, forgive so easily?

Sorting through the past, I've been:
Lied to,
Manipulated,
Taunted,
Hated,
Tormented.

Yet with time, I've forgiven all occurrences.

I've been manipulated so badly
that when I saw that person,
red hatred would flow within my veins.
They took my fragile emotions
and completely stomped on them.
For their own benefit.

And yet sooner or later, all is forgiven. Why?

I've been attacked verbally
both in person and virtually by close friends.
And yet I go to them and ask forgiveness.
I'm so afraid of being alone that I'd rather
have horrid people in my life
than a few close friends.

Are we, as humans,
so afraid of standing up for ourselves,
that we would rather have a plethora
of bad people in our lives,
compared to only a few good ones?

Are we, as humans,
taught to forgive and forget
instead of being true to ourselves?
We let others walk on us instead of standing strong.
We let others use and manipulate us,
and forgive them so we won't lose them.

*Is anyone else tired of these games?