(I use "actor" to mean both "actor" and "actress")
I've known a lot of actors, and I've been an actor myself. I've fallen for an actor, and I've kissed actors, both onstage and off.
Actors are the most frightening people ever to set foot on this twisted planet.
There is no inherent badness in theater itself; the stage crew, lighting engineers, and pit band all manage to evade the fate of the actor. No, the actor's plight is directly related to his job description: become someone else. Temporarily. Check your own persona at the door, and become your character. A good actor doesn't act by moving the way his character moves, imagining what his character would do in any specific situation. A good actor must become his character.
You know when that transformation has taken place the first time. You can feel it when you've ceased to become the Joe Bob the actor and instead are now a knight or a rock star or Jesus1. You look around the stage and see not other actors, but adoring fans or disciples. It's definitely a high; you leave all your real problems in exchange for scripted ones that can all be resolved in two hours or less. You're allowed to be bold in ways you never could otherwise without getting funny looks. You can carry out storybook romances and heated arguments, interact with other real people in ways you never would otherwise, and all with absolutely no consequences.
A high it definitely is, and addicting as well. Think of an actor you know: chances are this person randomly breaks into different personas in certain situations and has lots of different voices and accents they like to whip out on a regular basis. When in groups, actors will often break into various characters all at one time and play out improvised mini-scenes. But with the ease of moving in and out of different characters, and the sheer number of different characters an actor will play over time, the question becomes apparent:
Which one of those characters is me?
It's frightening to interact with actors who seem to have very little sense of "me" left. I've known plenty of them: moving from character to character, they never stop acting. All the world's their stage, and the curtain is never drawn. It's frightening to talk to someone, and wonder if they're the same person they'll be tomorrow, or if this is just another of their cute fronts that happens to fit well into the scene we're performing at that moment.
It's not that I dislike actors, that's not the case at all. Some actors are wonderful people, and I enjoy their company a great deal. I just tend to exercise an extra bit of caution in dealings with actors, lest I forget how natural it is for them to act.
1 All roles I've played