it means you hit your head XDF
one thinks with his/her head and feels with one's heart
It means Jealous
It should be obvious. If you try to nail jello to a tree it will not work because the jello will pull off from its own weight, every time. Nailing jello to a tree is a metaphor to denote an impossible task.
It could be many things (such as temporal arteritis), so go to your doctor.
NO
It means someone with a head full of nothing
If you mean the Jello mix powder right of the box - yes, you can. It isn't really 'raw'. The hot water is needed to dissolve the gelatin - not to cook it. Jello out of the box was a special treat when I was growing up.
If you mean Jello Biafra then no he is not gay.
people who do that are usually wondering what it feels like to finger their brain.
It means that the head is a world and the glass is always half full.
This could mean many things. It could mean the horse feels bad, or is in a bad mood, or it could be getting ready to 'herd' you or even attack.