I would want to because I am severely bored every day and few things alleviate it really. The rush, the act, the power. It would all feel great, especially getting away with it.
Not sure how I would get away with it. I guess my victims would be lonely suicidal people. I would lure them in with hopes for a better future, or just someone they can trust and be comfortable with. I would also need a house that I never use for anything other than the killings. The bathroom would be the main stage for all of this. Invite them over for a drink, get them to open up about their suicidal thoughts as the sedatives I put in their drink kick in. When they are delirious I would move us to the bathroom, which will be covered in plastic. Put them in the tub, with only a hole for the drain. I would wait for them to become conscious again, which by then, they will be unable to move due to their hands and legs being taped together, and then I would bleed them out. Comforting them as they slowly drifted into eternal rest, listening to their last thoughts. The clean up is self explanatory. Everything is in plastic, so just dispose of any bloody plastic. They would already be in a bathtub that is lined with plastic wrap, so wrapping them up would be easy. I guess I could put them in a refrigerator box or something and move the body to my truck. Which I would then take to a secluded area in the woods somewhere, probably out of state, and bury the body.
That would be cathartic.