Senoufou, I would once have agreed with you about it being a filthy habit - especially the people who chewed with their mouths open and talked at the same time - but I found it useful when I was working in an office, with no contact with customers, because it stopped me from eating other stuff. It would be tempting to eat if I became bored or demotivated, but the chewy stopped that very effectively.

Leaving chewed chewing gum all over the place IS a filthy habit, though.

Lonnie Donegan - Does Your Chewing Gum Lose it's Flavour?