I would argue that there are many better phrases, which don't necessarily translate to "goodbye", but are used instead of sayounara when saying goodbye to your boss or a customer.
To your boss, it's much more natural to say お疲れ様でした otsukaresama deshita when they leave work, but that roughly means "thanks for working hard". If you're leaving before them (which you shouldn't! :P), you say お先に失礼します (osaki ni shitsurei shimasu), roughly "I'm going to be rude by leaving first".
Well, you get the idea. So I wouldn't say sayounara is used in daily conversation.
Goodbye may seem forever. Farewell is like the end.
I came over a video a few years ago portraying the japanese teaching system. They were saying sayonara basically started as a bad joke about a high amount of dropouts. Or was at the time. The teacher who started it was teaching sophomore years and the school was loosing a few students every week