the word 'goodbye', when you look at it closely, seems like a perfectly harmless word. No sharp edges or harsh sounds - they're all soft consonants - Guh- duh- buh- simple, rudimentary utterances - the innocent cooings of an infant, before a betrayal of cruel R- sounds, sharp T- sounds and harsh S- sounds crowd them out. Examine the vowels. An extra O so you aren't surprised by the D, giving you extra time to prepare yourself, to pat your pockets and clear your throat before the final syllable hits. And then the ending sound, which is of course important, as it is the part that lasts the longest, the final impression, the part that's left echoing in the caverns of your heart as the train departs, as the image fades, as the car pulls away. The 'ah' sound unlocks your jaw and the 'ee' wrestles it into the skeleton of a smile, your mouth compelled to play along in a show of grim joviality. Indeed, everything about this word seems to have been designed to let you down gently.
I don't think there's any one correct way of saying goodbye, but I do think that there are an almost infinite number of ways to screw one up. The word is sometimes shortened to 'bye' in an attempt to hasten the affair, like ripping off a band aid quickly or cauterising an open wound, but this seems to accomplish nothing - apart from introducing a sense of curt abruptness to the ordeal. Some have suspended their use of the word entirely, opting for more pleasant alternatives; 'see you,' 'cya,' 'laters', 'ttyl,' only resorting to the word when all other valedictory remarks have been exhausted. However, there are certain unfortunate occasions where no other word can take its place, where the sting is undeniable, the terrible salt and bite.
It's not the pronunciation or spelling that makes it hard to say. it's not the word itself that's hard to hear - it's what it stands for, what it represents. It's not the taste that's hard to stomach - it's knowing what you've killed to make it. No point sugarcoating a pill if its contents are poison. It is not the sound that is troubling, but the deafening silence that follows.