Very => more than usual,
So => really, truly,
"So", and "very" have similar meaning and purpose..
This cake is very good.
This cake is so good.
This cake is really good.
This cake is truly good. =>
=> we are saying that the cake is good and we are satisfied with it.
This trip is very boring.
This trip is so boring.
=> we are saying that the trip is boring to us and that we are dissatisfied
"Very, so, really, truly" just make "good" and "boring" stronger in meaning
Too => more than it should, extremely
It usually has a negative meaning, but not always
This cake is too good = I love this cake so much that I could eat all of it
This trip is too boring = I really dislike this trip and I wish I could stop it
She is too good at shooting = her shooting skills are really good and better than mine. I wish I could be like her, but I know I can't.
This car is too fast= car is fast but not safe