"I prefer to feel the pleasure myself. Though, they do hold some appeal in some situations."
There are strap ons that are designed to pleasure the one wearing it as well.
"But dropping hot wax on another person?"
Don't knock it 'til you've tried it, it's amazing~
Do the proper research though, some candle waxes aren't really designed for human contact. I've had my best luck with the ones from Twisted Monk.
"Asking him/her to kiss your boots?"
It's no fun to just do as you're asked, got to make them work for that level of control, have them feel like they earned it. To start with asking in this case is pathetic and just shows weakness on the part of the Dom, as a Dom who knows what the fuck it's doing would work to make you desire kissing aforementioned boots. They're just lazy fucks who don't deserve to wield such power otherwise.
"Slapping his/her face so hard it leaves a mark?"
The sheer mix of audacity and lust can make it a fun combo.
"Humiliation?"
Depends on the level of it and what boundaries are/aren't there.
"Just thinking about it is kinda depresses me."
Finding the right partner is more important than the act itself. BDSM can be unpleasant even for those who are deeply attached to it if it doesn't fit their desires.
That relationship was with gia. Btw, have you seen his parting gift to you?
http://www.sociopath-community.com/topic/2014-01-02/farewell-batshits-a-parting-gift#60272
(Edit: Shit. Others should not scroll down that that thread. I repeat, for your own good, do not scroll down that thread.)