What is the purpose of adding -어/아 버리다 to other verbs? 버리다 on its own means "to discard, to give up". Is it adding intensity to the the first verb? Is it only used with verbs that have a negative meaning (무너지다, 망치다) or can it be used with positive verbs?
쌍둥이 건물은 완전히 무너져 버리고 말았습니다.
완전히 재미를 망쳐 버렸어.
When "버리다" is used as an auxiliary verb after the main verb, It shows the action or act of the main verb has already done, or just emphasis the main verb, like the verb "do" in English.
As the result, the talker feels something miss, or on the contrary to this, he feels something comfort. Therefore, It can be used any verb, not only negative meaning, but also positive meaning.
밀린 숙제를 싹 다 해 버리고 나니, 기분이 좋다.
그는 옷에 묻은 먼지를 훌훌 털어 버렸다.
항상 조금씩 저축을 하다 보니, 어느새 부자가 돼 버렸다.
잡으려고 손 내미니, (나비가) 날아가 버렸네.