Embarrassment

Quedarse/estar cortado/a [] Lit. To be left cut/To be cut. To lose one's nerve/tongue (out of embarrassment).
Example: Intenté hablar con ella pero me quedé cortado [] I tried talking to her, but embarrassment stopped me.

Ser un/a cortado/a [] To be a very shy and self-conscious person.
Example: Para esas cosas soy muy cortada [] I'm very shy about that sort of thing.

Fear

(No) tener cojones/huevos [] Lit. To (not) have the testicles/eggs. To (not) have the balls.
¿A qué no tienes huevos para decírselo? [] I bet you don't have the balls to tell him.

Acojonarse [] To get/have your balls in your throat (from fear).
Example: El examen de conducir me acojona mogollón [] The driving test scares me to death.

Happiness

Estar como unas castañuelas [] Lit. To be like castanets. To be very happy.
Example: María está como unas castañuelas con su nuevo novio [] María is as happy as a clam with her new boyfriend.

Estar loco/a de contento [] Lit. To be crazy with happiness.
Example: Están locos de contento con el bebé [] They are delighted with the baby.

Sadness

Un bajón [] Lit. A big drop, for example when travelling on a plane. Figuratively, a downer.
Example: Le ha entrado un bajón desde que rompieron [] He's been on a downer since they split up.

Depre [] Short for depresión. Used when you're heading for depression but not quite there yet.

Ser (un/a) depre [] is to be a pessimist.
Example: Es un tío depre - siempre contando sus penas [] He's a pessimistic bloke - always talking about his problems.

Estar depre [] To be down.

Confusion

Estar zombi [] Lit. To be like a zombie. To be scatterbrained, to think or act aimlessly.
Example: Hoy no puedo concentrarme, estoy zombi total [] I can't concentrate today - I'm completely scatterbrained.

Estar en Babia [] To have your head in the clouds. Babia was the retreat of early Castilian kings in the Middle Ages: when they were there, they didn't have a clue what was going on.
Example: Es un incompetente total, siempre está en Babia [] He's completely incompetent, his head's always in the clouds.

Madness

Tener un cacao mental [] Lit. To have a mental cocoa. To have your mind in a mess.
Cocoa needs a lot of stirring, hence the feeling in your head.

Estar como una cabra [] Lit. To be like a goat. Figuratively, mad as a hatter.
Example: Se quiere ir a vivir a Siberia - está como una cabra [] He wants to go and live in Siberia - he's mad as a hatter.

Faltarle un tornillo [] Lit. To be missing a screw. To have a screw loose.
Example: ¿Para eso llamas a las dos de la madrugada? ¿Y a ti qué tornillo te falta? [] Is that why you're calling at 2:00am? What screw do you have loose in your head?