Answers depend on each individual persons who smelled it! (The cologne backfire video seems does not help answer the question)
Smell comes differently to every individual person observing or receiving it, and thus they have the power to accept or refuse the smell or scent, and thus may or may not, tend to react from it. Every individual person may or may not be aware of certain smell/s that other sensitively observed such smell/s; and likewise others, may or may, not tend to react to public of what have he/she smelled. Exception to this, are people who did not smelled it who were just influenced by the reactions of the others who have smelled it, thus making the smell as bad as it seems, even though it is not (scent of Durian is good, but when heard from others... it becomes bad)
Now, by analyzing the above explanation, each person will have a distinct Good Scent and Bad Scent. Good smell will be anything that you like, likewise Bad Smell is what you don't like; which is differently to other people.
Secondly, the power of our brain also influences us to accept, refuse or ignore what every we smelled, even hear, think, felt or tasted. So, even how Good or Bad the smell is, the scent may be changed depending how our brain acted on it. (try to ask your wife how she managed to be on your side when you are drunk or having such a body odor)
Thirdly, IMMUNITY. If our senses are immuned to such stimuli, then... the question above becomes a joke itself! So even if we don't enumerate the smells we known from our lives, it still depends on the one who is smelling it/observing it.
Lastly, there is another thing smells can be annoying. Any smell that is associated with pheromones that tends us to react negatively or to move away from such smell is the worst smell you can ever smell. Personally, I smelled twice or thrice, from a woman, dark-toned skin (not black)... the smell really turned me away from her. Much worst than Bombay people. And even though she used deodorant, the smell of deodorant is good but what comes with it is the scent that drives me away from her. I believed, from one of the numerous articles that I have read, her natural scent (pheromones) are caused by a sexually imbalanced person.