This is a really modern slang phrase that I’ve been hearing more and more lately.  I noticed a friend of mine use it the other day, and I heard it on a couple of new TV shows.  If you “drink someone’s Kool-Aid” it means that you are listening to their opinion too much.  You almost forget to think for yourself and are easily convinced by the other person.

Here is a real life example:

I can’t believe you invested all your money into that one stock just because one of your friends said it was a good idea.  I think you are drinking too much of his Kool-aid.  Be careful and think for yourself.

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