My personal reason for being NIMBY is pretty simple though: I just want to sleep at night. and since municipal rules are hardly ever enforced in high density areas, I'll have to deal with kids screaming, idiot drunks trashing the place at 3 am, graffiti and people having parties at all hours of the night and day with the cops telling me to just deal with it because I live in a high density area. So when they try to build more on top, I'm like "Err, no".
I literally dont care if my property value dropped to zero, as long as I can sleep without needing earplugs. I already have to run the A/C or heat twice as much as I should because I can't open the windows without "enjoying" whatever activity my neighbors are doing that involve screaming on top of their lungs.
Besides, I live in one of the top 10 most densely populated neighborhoods in the country, and then people want to add more. ::shrugs::
In my home country this was not an issue because people could respect each other, and rules were enforced. In that case, build as much as you want in my backyard.
It sounds like you came from a nice, civilized country. Why then did you move to whatever 3rd-world hellhole you currently live in? It sounds like you'd be happier going back home.
NIMBY has many reasons behind it, and one of them is trying to increase housing values. Other things are guarding precious "free" parking spaces, being old and not liking change, or being afraid of changes effecting the quality of your children's school and other things.