Shouldn't modals be vertically centered instead of appearing at the top?

Created by: pedrocatre

So this is not a "how to" question because this answer: http://stackoverflow.com/a/20444744/3094399 on stackoverflow allowed me to solve my issue and implement this behaviour.

The questions then are:

• Why is modal vertically centered not the default? Seems a lot more user friendly to me and to my users. But since it seems I always find sensible defaults on bootstrap, maybe there is a very good reason behind this that I'm missing.
• In case there is a good reason would it make sense for this to be configurable (where the modal appears in the window)?

Thanks

Edit: the stackoverflow solution I pointed to as an issue if the modal is bigger than the window. This can be fixed with a conditional statement but there is another answer that only uses HTML and CSS that works well and I think is better http://stackoverflow.com/a/24829651/3094399