There are many reasons why the transition from Adventist to atheist is easy:

The Bible
Adventist – Know it well.
Atheist – The book that freed many tortured souls, and made them atheists.

Beer
Adventist – Forbidden.
Atheist – Awesome!

Sex
Adventist – Good if with someone you’re committed to for life, even though you have no idea of sexual compatibility prior to said commitment.
Atheist – Awesome!

Bacon
Adventist – Forbidden.
Atheist – Mmmmm bacon…

Origins
Adventist – Blind acceptance of an ancient myth that has been proven wrong by every field of science countless times.
Atheist – Acceptance of scientifically validated facts and hypothesis.

Separation of Church and State
Adventist – All for it.
Atheist – All for it.

Minority Religious View
Adventist – Used to it.
Atheist – Used to it.

Prophecy
Adventist – Six years after a severe head injury, a young woman in the midst of the Great Disappointment starts seeing visions, obviously the work of God.
Atheist – Bull shit.

Eschatology
Adventist – In the Great Controversy the world is a stage, but we’re just chess pieces in somebody else’s battle.
Atheist – If we don’t do something, we will not have a planet able to sustain life…

The Time of Trouble
Adventist – Hiding in the woods being hunted like animals.
Atheist – Back in the city partying.

Monisim vs Dualism
Adventist – Monists as far as humanity goes, dualists about the rest of the universe.
Atheist – Monsists about everything.

Heaven
Adventist – Like camp meeting, it just doesn’t end…
Atheist – Boring…

Hell
Adventist – A Greek myth.
Atheist – A Greek myth.

Education
Adventist – Very important.
Atheist – Very important.

Logic and reason
Adventist – Great as long as it’s subject to scripture.
Atheist – The best thing since sliced bread.

The Scientific Method
Adventist – Great as long as it’s subject to scripture.
Atheist –Better than sliced bread.

All it takes is for an Adventist to view the Bible for what it is, an ancient mythological text; accept the rest of science; and extend the monism outside of oneself and you have yourself an atheist. As such, it’s never surprising to find out that classmates from high school and college have come to the dark side, it’s surprising to find the ones who haven’t yet…