Fuck

Fuck is the only fucking word that can be put fucking everwhere without hindering your fucking ability to comprehend the fucking sentence. Can be used to express annoyance, anger, or unpleasant surprise. Can also mean to have sex with.

"Oh fuck, I broke the vase!" - Expressing unpleasant surprise
"Lets fuck." - Asking for sex
"Fuck you!" - Expressing Annoyance or anger towards a specific thing.

E

"E" is used when there is no response you can think of.

"The weather is nice today."
"Yea, it is."
*awkward silence*
"E"