A common tenet in user interface design is to be consistent, especially to be consistent with de facto standards. It's certainly a good goal, but I think that kind of consistency can be pushed too far. I recently thought of some real world examples: humble, ordinary, every day doors.
Doors share a common functional requirement: be closed sometimes and be open others. That leaves a lot of room for design though, like what color should it be? Or, more importantly, which way should it open?
The De Facto Standard
Doors in offices, bedrooms, bathrooms, etc. tend to open inwards. Why? Because a bathroom door opening outwards could suddenly thrust a large solid object into a public walkway. Black eyes, broken noses, and other hilarity ensue.
The Exception
There's a major exception to this rule. Public places where there are likely to be crowds like stores tend to have doors that open outwards. Why? Because a dangerous fire is far more likely to occur inside than outside, and if one did occur then a rushing crowd could jam an inward opening door closed. Panic, trampling, and other hilarity ensue.
The Exception to the Exception
There's a major exception to the exception to the rule. An airliner is certainly a crowded public place where you would want to quickly get people out in an emergency. Yet the door opens inwards. Why? Because at altitude the airplane will be pressurized. The inside pressure will be significantly higher than the outside and must be contained. The doorway is a significant weakening in that containment, but a door that opens inwards works just like a drain plug. The pressure difference keeps it firmly sealed and in place. A door that opened outward would be very likely to, um, open outward. Ejected flight attendants, hypoxia, and other hilarity ensue.
The Take Away
De facto standards are good and often have good reason to exist. But they don't always apply. Exceptions and exceptions to exceptions sometimes make more sense. Following a standard is no substitute for doing actual design.