If you're staging a meeting or a training session, you'll welcome the opportunity to lay the room out according to the optimum design.
It may be that you need a 'boardroom' set-up, with everyone around one table, or that you require more of a 'classroom' set-up, with chairs and desks facing the front of the room.
Each meeting or training session will be different; it all depends on the purpose of the gathering and the strategy you're adopting to pursue your intended goals.
If you're hoping to foster collaboration, it makes sense to have everyone facing each other. But if the bulk of the session involves a speech or presentation, the priority should be ensuring everyone has a clear view.
Some meeting and training rooms are difficult to customise. It may be the case that heavy furniture is in place which can easily be moved, or there simply isn't the floor space to deviate from the standard layout.
As an organiser, this gives you limited options. It begs the question as to whether you should be using the facilities in the first place.
Staging a meeting or training session in an unsuitable room can create various problems; you could have cramped participants, be unable to provide everyone with a desk, or some attendees may have a restricted view.
The last thing you want is for the facilities and room set-up to become a distraction. You'll know you've got the layout right if nobody notices it and nobody complains.
Choosing a specialist training or meeting room, which is sufficiently large, has a supply of natural light and can be set up to suit your needs, increases the chances of the session being a success.
Ultimately, you want the people who attend to focus on the items on the agenda or the training plan, and ensure the time spent in the room is used as productively as possible.