I am green but I am sweet what am I? do you know?

I’m known for how I bend, and how I protect. Against the former I fend, and the latter, deflect. At times I’m used as slang for myself, while referencing how good I am for your health. I’ve many more uses, but one last good clue: If you’re me, your opponent is glue.

I exist so meetings that should have been emails can happen.

What do you use to stop someone from advancing?

Above your brows I boldly spread, A patch of calm before what’s said. I wrinkle when you think or dread, And shine when overheated.