Come Together boasts some brilliant nonsense lyrics and a simple but effective vocal melody - pretty much the whole verse uses just 3 notes C, D & F (the b7, Root & b3).
Not only is the song carried by the unique lyrics (just like many Dylan songs) but the unusual phrasing also prevents it getting tiresome. Almost every line in the song stays off the first beat (we'll call that Ticket 39). And that's not all. Each line really starts on the 4th beat, immediately after the preceding line. We get two syllables, then a rest before the remainder of the line
So the lines that read
Here come old flat top
He come grooving up slowly
He got joojoo eyeball
He one holy roller...
Here come old flat top, he come
Grooving up slowly, he got
Joojoo eyeball, he one
As well as being interesting just because it's odd, it makes you anticipate what the next line may be.
The Blues or not the blues, that is the question...
The use of the b7 (C natural) and especially the b3 (F natural) gives the impression that they're using Ticket 22 (bluesify your melody) but the guitar part never plays the maj 3rd (F#). So like Rain & Love You To they are conning you into hearing notes that aren't there.
We do get an F# in the chorus on togethER RIGHT now over a Bm chord, which gives us a fantastic contrast between the two sections (Ticket 5). Ringo also helps out by avoiding the snare drum in the verse but using it in the chorus.
Come together, right now is also the highest point of the song pitchwise. Another example of putting your key lyric on the highest point of the melody (Ticket 27).
And McCartney (for once) is pitching his harmony vocals below Lennon.
Next time - more on the arrangement & structure.