Basically they are the same, but elnézést is a bit more formal.For example when you are late from a business meeting it's better to say elnézést, but saying bocsánat works as well.
Bocs, szia...as long as it's correct, I'll use the words with the least letters as much as possible lol
Yeah true, although "bocs, szia" is informal, and "elnézést, viszlát" is formal. Not unimportant when you want to say goodbye to your parents-in-law :D
David Garcia: Shorter forms are used in informal situations, longer form is the more polite. When you want to impress somebody, also use the longer. They will be pleased to hear that :)
Whe you should use the short version of some words? Example Bocs vs Bocsánat, Viszlát vs Viszontlátásra
"Bocsi" is accepted - I just tried it. Otherwise, I commonly use "Bocsánat", "Bocs" and "Bocsi" when in Hungary depending on the level of formality I wish to convey (eg. the position of the colleague I am talking to.)
I thought 'helló' is used upon encounter, not when parting, bit let it be - Duo now accepts this as well. Thanks.
I've had frequent assignments in Hungary through work and can confirm that - as surprising and as it sounds - the expression "Háló!" as well as the expression "Szia!" are both commonly used for both meetings and partings, therefore for both "Hi!" and "Bye!"