Because they are 'that good'? I realise different songs may affect people differently 
I have lots:
The last part of Do the right thing, Simply Red
The last part of Light my fire, Will Young
The whole of Sandstorm, Darude
The chorus of Love Love, Take That
The chorus of The Flood, Take That
The whole of Praying for time, George Michael
The whole of Sing Hallelujah, Dr Alban
The last chorus, to the end Confusion, ELO
The last bit, to fade, Rise, Gabrielle
All of Don't You, Simple Minds
All of Shine, Years and Years
All of Paradise by the dashboard light, Meatloaf
All of Home By The Sea, Genesis
Just off the top of my head