I like happiness as much as the next guy, but it's not happiness that sends one in search of truth.  It's rabid, feverish, clawing madness to stop being a lie, regardless of price, come heaven or hell.  This isn't about higher consciousness or self-discovery or heaven on earth.  This is about blood-caked swords and Buddha's rotting head and self-immolation, and anyone who says otherwise is selling something they don't have.

Nirvana is an experience of the Unconditioned which defies any description.  Any description of Nirvana is not a description of Nirvana, and that is the most that can be said about Nirvana.  There are no reference points in Nirvana on which to base a description.

Paradoxically, as the mind becomes simpler, it can perceive greater complexity.

Developing the capacity for clear light dreams is similar to developing the capacity of abiding in the non-dual presence of rigpa during the day.  In the beginning, rigpa and thought seem different, so that in the experience of rigpa there is no thought, and if thought arises we are distracted and lose rigpa.  But when stabliity in rigpa is developed, thought simply arises and dissolves without in the least obscuring rigpa; the practitioner remains in non-dual awareness.