] Limerence has certain basic components:
]
] - intrusive thinking about the object of your
] passionate desire (the limerent object or 'LO'),
] who is a possible sexual partner
]
] - acute longing for reciprocation
]
] - dependency of mood on LO's actions or, more
] accurately, your interpretation of LO's actions
] with respect to the probability of reciprocation
]
] - inability to react limerently to more than one
] person at a time
]
] - some fleeting and transient relief from unrequited
] limerent passion through vivid imagination of action
] by LO that means reciprocation
]
] - acute sensitivity to any act or thought or condition
] that can be interpreted favorably, and extraordinary
] ability to devise or invent "reasonable" explanations
] for why the neutrality that the disinterested observer
] might see is in fact a sign of hidden passion in the LO
]
] - buoyancy (a feeling of walking on air) when
] reciprocation seems evident
]
] - a general intensity of feeling that leaves other
] concerns in the background

Good definitions and FAQ on "limerence", a state in which I occasionally find myself.