alright well theres alot but the integral part of it is that its ritual and transformation. its indulgence and addiction. its substance and want and need. its complicated but basically imagine what alot of recreational drug use is like.
vampires get drunk off of the blood that also helps supplement nutrition for their supernatural bodies. blood isnt the only thing they eat but indulgence in the blood is the most crucial of things.
the only taboo that is shared amongst all vampires is to not drink another vampires blood. its a thing that has terrifying implications for vampires, for the blood, and for all beings that have blood. vampire blood is a tainted substance that is very difficult to purify. vampires already have all of their blood become this. too much vampire blood in one being can lead to a terrifying oversaturation physically and mentally.
vampires can be good people and they can also be bad people. they're inbetween beast and man and can have the good of both and the bad of both. they need the blood but they do not need to kill or maim or hurt others in any other way then just getting enough blood to sate their thirst and continue their mirth.
some overindulge, some have fowl goals they wish to acchieve, some merely just werent made for the life and they made an honest mistake. its complicated to say what makes a "bad" vampire other than at the end of the day, what they do to others and what they do to themselves.
vampires are very slow to let another being become vampires because of this. being a vampire is not a life for everyone.
The process of becoming one is not an overnight decision. its a ritual of consuming trace ammounts of fresh vampire blood over a time period of about a year, sometimes longer. too much too quick could cause the transformation to go wild and either kill you or drive you insane. some even quit halfway through. the decision isnt necessarily cemented until the end. bodies tend to reject vampire blood.
Vampirism can be "cured" but this as well is a major decision and a long term process. vampires are drunk on blood and to stop being on you need to go "sober". this involves drinking certain special bloods that have less of the pollutants that makes vampires drunk as they are, and other ritual fasting and such.
at the end of sobering, a vampire can once again be mortal with no more blood thirst. they then can live the rest of their mortal lives and age until death.
very few vampires go back though, the mental and physical toll of unbecoming is far more than that of becoming.
also theres other stuff but ahahigh i need to stop or ill be here all night