Do you ever check on your past toys to see how they are holding up? I know you don't give a shit about them, but do you for example check their Facebook or talk to people about them, hoping they are showing signs of permanent emotional wounds?
How do you like your past prey to act if you bump into them?
I only look up past victims when I am bored beyond reason. I take spells where I want to extend my reach as far as it will go (usually directly before or during the "harem gathering" stage of my 'dating' cycle). I will, during this time, contact everyone I still have the number of, and keep fairly steady contact (daily/every other day) for about 4 days to a week, then I cut them all off for another 6-8 months until I decide to feel around again. It's just a sad mix of boredom and mild curiosity. (Not to say I wont fully cash in on any opportunities during this process.)
The only two reactions that particularly amuse me are excitement because they missed me, and fear/dread (which usually leads to me causing them hell for a bit before getting bored/moving on).
I agree with Kao here, facebook/friend stalking is strictly for active targets. Although, if my primary form of communication with them is online, I generally 'brush up' on what I've missed so that I can seem on the same page with them still. I have only stalked one former pet, while they were former, but that is because she remains desired. Curiosity isn't relevant if the information is useless.
My father said he knew I was a bit off ever since he took me to see Jaws as a kid, and I rooted for the shark.