Why do some parts of a song sound better than others?

Question

Disclaimer

I have no sophisticated taste in music, I most of the time listen to what's on the radio (which is mostly pop and charts). I have a basic understanding of what a note is and what constitutes a melody, but that's about it. Also, since taste obviously varies, this question ventures on the verge of legitimacy, but I want you experts to be the judge of that.

Background

Whenever I like a song seldomly I find myself being fond of the whole piece but rather only certain parts that sound very "melodic" to me (unknowingly if the word "melodic" is used correctly here). See my examples below:

• Song 1: From 00:45 to around 01:04 sounds very appealing to me

• Song 2: Right from the start until 00:21 evokes strong, positive emotion in me (without seeing the music video or experiencing any
  other sensory stimulation), which I again attribute to its sounding
  good to me

I have noticed that I frequently come across these appealing parts in songs that are in the general charts, i.e. composed and released to be liked by as many people as possible. This indicates to me that there is some common part in that kind of songs.

Questions

Music makes happy, (apparently) aides finding focus (athletes, ...) and does many other good things. To honor this I want to get to the bottom of why certain parts of songs sound good to me (i.e. evoke positive emotion) while others don't (for me).

Regarding the samples above, do they bare any music theoretical resemblance to each other?

What would be their music theoretical significance?

Answer 1

Both pieces feature a passage that is played/sung twice. We like repetition. The first piece has a quirk:there is a lot of musical action (chord change, accented note) happening on the last beat of a 4/4 bar. That is a little unusual because it's usually more likely to occur on the first and third beats in 4/4. There is a little more forward motion in this section than in the opening of the song, so the listener has more to 'latch on to'. However, most listeners would be more likely to bond with the next section, the chorus, which contains the 'kryptonite' hook. So it is interesting that you find this section more enjoyable than the chorus. The second piece features a heavier syncopation in the melody; most listeners tend to find such syncopation speech-like and stimulating, as long as there is some sort of rhythm in the background for reference. Both pieces feature chord progressions that make musical sense and incorporate the drama of using the minor chord built on the 6th degree of the major scale. Using the relative minor in a major chord progression is a commonly-visited gold mine: it adds momentary drama without scaring the horses. Both excerpts are 'of a type', so you are likely to have heard something similar to each before in popular music.