Although it's about music, I guess "What are you listening to?" isn't the place for a mini-lecture like this.
It has now become common knowledge that "She Loves You" was partly inspired by "Forget Him" (a recent hit by Bobby Rydell, one of the "boy crooners" of that period). But what's well known is merely that they were both "advice songs", i.e. the singer is giving advice to a second party about a love affair with a third party, and "Forget Him" inspired the Beatles to write their own "advice song."
That's true, but it's not nearly as important as the OTHER link between the two songs, which nobody ever mentions, except a few musicologists who are analyzing songs.
In the Beatles' famous refrain
"She loves you, yeah, yeah, yeah,
She loves you, yeah, yeah, yeah,
And with a love like that, you know you should be glad."
they used a very unusual chord sequence. In the key of G, it's
Em -- A7 -- Cm -- D7 -- G
which analyzes as "vi -- V7/V -- iv -- V7 -- I"
The change from A7 to Cm is the unusual part.
Listen to "She Loves You" at
"Forget Him" was just a teen-pop ballad; but its composer, Tony Hatch, was a real professional and wrote many fine pop songs, such as the hits of Petula Clark.
In "Forget Him", on the lines
"Don't let him tell you that he wants you,
Cause he can't give you love which isn't there."
we hear a chord sequence that (in the key of G) would be
B7 -- Em -- A7 -- Cm -- D7 -- G
So, starting with the Em (on "wants you") we have exactly the chords of the "She Loves You" refrain above.
Listen to Forget Him" at
Note further that Rydell sang the words "she can't give you love which isn't" to the notes "G, G, F#, E, G, G, F#, E" over the A7 chord, and the Beatles then sang the words "yeah, yeah, yeah" to the same notes "G, F#, E" over their A7 chord. The similarity is obvious once you hear it.