Top 5 worst songs as of 9 May

These 5 songs are by far the worst songs I've ever heard- the melody, the vocals have driven me crazy... Here are the songs:

Note: I am not spreading hate, I am just listing the songs that need A LOT of work, especially the songs that clinched the top 3 spots.

No 05. GUY by Lady Gaga

No. 04: Ghost by Ella Henderson

No 03: Hello Kitty by Avril Lavigne

No 02: Ain't It Fun by Paramore

No 01: Birthday by Katy Perry