Search Results: fear of rejection or shyness

lim·er·ence: near-obsessive form of love... the state of being involuntarily infatuated/obsessed with another person, and characterized by a strong desire for reciprocation of one's feelings but not primarily for a sexual relationship... Thoughts of the limerent object (or person) are persistent, involuntary and intrusive... This may be caused by low serotonin levels in the brain, comparable to those of people with OCD.
Limerence is characterized by intrusive thinking and pronounced sensitivity to external events that reflect the disposition of the limerent object towards the individual. It can be experienced as intense joy or as extreme despair, depending on whether the feelings are reciprocated...
Basically, it is the state of being completely carried away by unreasoned passion or love, even to the point of addictive-type behavior... Sometimes fantasizing [about the person] is retrospective: actual events are replayed from memory with great vividness...
Physical contact with the object is neither essential nor sufficient to an individual experiencing limerence, unlike with one experiencing sexual attraction...
Other characteristics [of limerence] include acute longing for reciprocation, fear of rejection, and unsettling shyness in the limerent object's presence... feelings of limerence can be intensified through adversity, obstacles, or distance—'Intensification through Adversity'.[14]...
But when rejection seems likely the thoughts focus on despair, sometimes to the point of suicide... Although the direction of feeling (happy vs unhappy) shifts rapidly, with 'dramatic surges of buoyancy and despair',[15] the intensity of intrusive/involuntary thinking alters less rapidly, and only in response to an accumulation of experiences with the particular limerent object...
Limerence can last from a few weeks to several decades, with the average being 18 months to three years.[22]

Is it the fear of rejection, insecurity, low self-esteem, shyness, lack of confidence, your looks or a mole on your left cheek or everything?

I feel like life is too short to be worrying about if the person you have genuine feelings for feel the same way about you. Just go out there and freaking ask.