To completely buy into an idea or system, whether good or bad.

Micro marriging is when your partner manages your personal day-to-day tasks with you much like a Micro Manager at work.

Going along with what a crowd desires. Often used when a person changes positions on a topic.

To make a wholehearted, unconditional commitment (to some group, or idea, or plan) in contrast to choosing an alternative. It emphasizes a resolute decision (good or bad) in response to a choice.

This is a reference to the "electric Kool-Aid acid tests," which were LSD parties held in the San Francisco Bay area in the mid 1960's. Someone who was willing to drink the LSD-laced Kool-Aid had, symbolically, made a choice to join (if only for a few hours) a counterculture that stood against conventional society. Once you take acid, you're committed -- the trip lasts for hours and you can't cut it short or change your mind. Once you've drunk the kool-aid, you're firmly committed.

IMHO it is not about suicide: kool-aid isn't a symbol for poison.