Scale!

After watching some more tutorials one of the most important things we need to get right at the start of the game is the scale. 1 unit in Unity = 1 metre, a person for reference is about 2 metres tall. If the scale is way off (say we have a space ship 400 metres wide), the physics engine will mess stuff up. A 1x1x1 box will roll over pretty quickly if knocked, but if its 100x100x100 it will take ages