That’s the way it’s been since protozoa
I love my mother.
Last night, she is commenting on the difference between love and a crush—and up to this point, you must bear in mind, she has been speaking in strictly real-world terms, illustrated occasionally with anecdotes from her life in high school. And then: "But there's that obsessive quality to a crush. Because all you can see is the nymph. And then you move in with the nymph and she turns you into a tree."
Something must be done with this.
Last night, she is commenting on the difference between love and a crush—and up to this point, you must bear in mind, she has been speaking in strictly real-world terms, illustrated occasionally with anecdotes from her life in high school. And then: "But there's that obsessive quality to a crush. Because all you can see is the nymph. And then you move in with the nymph and she turns you into a tree."
Something must be done with this.

no subject
So I would say that the danger sign of an unhealthy crush is when the person with the crush insists on calling it love and thereby insists that it is "more" than a crush. Hence the wisdom of the original anecdote; it's easy to get turned into a tree if you aren't careful.
(Cue the Lumberjack Song here....)