Lyric discussion by stickbreaker 

Cover art for Spit It Out lyrics by Hardcore Superstar

It's probably about people who don't speak their mind and how upsetting that can be.

The last verse, I would guess, is about wishing you had more courage to actually tell people that you can see through them when they don't speak their minds. This unability to tell people this makes you see in red and wonder why you just can't...