I don't know if I can come up with favourite parts for every song, but I'll name a few!
Make Believe - Like a lot of you, I'm in love with the angels on fire part. That lyric inspired me enough to start writing again. Literally as soon as I heard it my brain was like "Hey, remember that BSB fic you were working on? You should probably start writing it again as soon as you get to work." So I did lol
In A World Like This - The beginning of the chorus when they sing "In a world like this where some back down." Specifically the way they sing the word "back." The harmonies sound very classic BSB to me and it has a very Backstreet's Back/ Millennium vibe.
Feels Like Home - The southern beginning, which is apparently Kevin LOL. Whoever it is I'm in love with it! It's silly, but it's also something they've never done before which I appreciate. I also like Nick's part in the second verse where he sings "Where the party don't stop." He has so much power behind it and I picture him dancing like a fool every time I hear it LOL
Soldier - Like Julie said, the part where Nick sings "But somebody shot you down, right in the middle of a war outside..." is amaze! Love it.
Love Somebody - "I'm so in love I could die right now." just makes me giddy and grin every single time because I can just picture Nick being so happy while writing it. Also the silly caveman line LOL.
Hot, Hot, Hot - That "Brrr!" part after they talk about the ice cold bath or ice cold shower or whatever it is LOL. It's so ridiculous.
Show 'em - Nick singing "You find the truth in a child’s eyes when the only limit is the sky" Guh he's just so good, you guys! I cannot.
There are more but those are the ones that jumped to my mind right away. Also not surprisingly they are mostly Nick. Clearly I am a Nick whore, but you guys already knew this LOL. He just sounds so amazing on the album!!