Think of it as analogous to things like computer crashes, core dumps, etc. To a first approximation, the brain is a computer and can fail catastrophically in analogous ways. And most people aren't running Erlang but something very fragile.
It's just that meditation is somewhere between daydreaming and sleeping. Feels like something about as far from any conceivable failure points as possible.
ah no, it's not a lightbulb. Your mind may feel like that to you based on how much you've dug into it, but it's definitely way more complex than that -- and you know it objectively. It's a 1 kg mass of billions of neurons with billions of connections. It's obviously more complex
no we don't, that's why this conversation will go nowhere... but the thread I quoted is 100% empirically true as an overview of the consequences of meditation practices. Make of that what you will.