To be absolutely brutal and honest with you, nobody cares about I look forward to hearing from you.. The practical reason is that it's one of the various standard and conventionally polite ways to end the body of the letter. It's just a standard exit.
1 In some cases, liver failure causes this taste to occur. 2  Gastroesophogal reflux disease can cause the salty taste (even when no pain is present). 3  Some medicines can make everything taste odd. for example the drug enalapril, which is a drug used to prevent heart failure.
On the other hand the salty taste could come from acid reflux. When acid from the stomach washes up into the esophagus and mouth, which commonly happens at night when you lay down, this can cause irritation to the back of the throat, cough, and a bitter or salty taste in the mouth when you wake up.