I don't really know much about music so I might wrong here and there but this is just from my personal opinions.
1. Really loud backtrack and too much processing. Idk is it the edm or very heavy autotune. Again, I might used wrong term. In short, whatever the producers add to it is just too much. This song is in the 'noise songs' category for me.
2. His high pitch vocal. I don't really know how to describe this the best but after I watched his mv, I run to Serendipity and his voice there is heaven. I like his vocal colour the most in Bts because it's unique. Idk why he thought he needs to sing in high pitch most of time. I don't really good in explaining this but in short his voice in Serendipity is extremely good and not forced when you compare to this song. I like that side of his voice and vocals. He didn't overdoing his high pitch there. And you can heard his voice in Serendipity so clear but for Like Crazy, it's being overshadowed.
This is not a hate post, this is just my opinion. You can freely agree or disagree. I actually doing this post because I like Serendipity a lot like a lot and I like it the best out of all Bts solo songs. It's my comfort song. And I like filter too if it's not because of those two thing I stated above. But with filter, it's not as severe as this one.
Someone need to tell him, his normal vocal color is amazing already. Idk what's going wrong but he always sing in high pitch for these 2-3 years. Someone in Bighit need to be fired for that. I miss his real voice not the high pitch one. I might user wrong term but I hope you understand.