10dsw, you asked some posts earlier if there's any difference between BPD and HPD.
Well, the behaviours are very, VERY similar, and indeed some therapists may make a wrong diagnosis, but the core reason behind the disorders are slightly different - even though there is some literature which state that HPDs may decompose towards BPDs when they are under heavy stress.
Also, there's a high rate of comorbility (if I remember correctly it is around 30-40%, but I may be wrong).
If we want to make a very gross simplification, HPDs can be described as a more "high-functioning" and a lot more funny versions of BPDs.
However, BPD and HPD traits are different (even if they mix in a LOT of cases...), as well as the core reasons behind the disorders: BPDs crave for
validation, while HPDs crave for
attention (which in turn is a tool to get validation/sense of worthiness). Both stem from deep, deep issues with self-esteem.
Speaking about the need for attention in HPDs, this translates into behaviours like extreme flirtitiousness, the need to be "the life of a party", etc. This is why HPDs are, in general, so, SO funny!

You can find some interesting academic material here:
http://www.universitypsychiatry.com/cli ... _PICPs.pdf (histrionism)
http://www.universitypsychiatry.com/cli ... _PICPs.pdf (borderline)
http://maretwebproject.com/users/docs/histrionic.pdfhttp://maretwebproject.com/users/docs/borderline.pdfYou may want to read some Masterson's book as well.
In general, having to deal with cluster B people (put aside ASPDs or cluster B people with anti-social traits...they may be dangerous to deal with, better avoid) can be really, really funny and/or a unique (in a positive sense) and enriching experience...IF you can keep them at arms length (no romantic relationship) and manage their drama. Basically, this requires to enforce
strong boundaries...it's like playing with fire: if you're careful you may really enjoy it, otherwise you may get seriously burned.
Anyhow, I don't think you have problems in enforcing boundaries, given your sadistic tendencies...
As a side note, you sound a little bit as a cluster C personality...is it possible?