C'mon guys,
MC still traumatized by his past before he meet Takamine.
His problem not only about height. but way more than that.
and this "height" problem probably just an excuse to reject him in the first place.
there're lack of information about his previous crush, like how close they are before. is it almost the same like Takamine or not?
and the most important is.. "HOW LONG"? months? years? the higher you climb the harder you fall.
if so, then that its a surprise that he act like that toward her after realize his feeling.
That rejection really broke MC confident,
for some people after incident like that it will lower their expectation about being liked back or even noticed.
this why he denied his feeling toward Takamine. because afraid of rejection.
Because the worst thing about rejection is, not being able to talk again with someone you love.
awkward feeling,sad, worried and hate mixed into one whenever you meet her. and this made worse by our wimpy MC.
Until this point he used Takamine to run away from his past.
And now its time for him to face it and overcome it.
Its easy for us as reader to criticize him, about how stupid he is.
I once had this phase once in my life. trust me, the fear of rejection is real.
Calm down guys, its part of the drama and character dev.
and if you dislike Drama that much.. why the hell are you even here for...
and trust me, there're much worse drama out there than this.