Well that goes without saying, however when practicing in the dojo, (be it two line drills, or free style kumite) there needs to be an intensity and feirceness, otherwise you won't benefit from it. If you ever get in a position where you have to use your training, your assailant will be fierce and will be trying to hurt you, and will possibly try to intimidate you. Drills and sparring should emulate an actual confrontation as much as possible (without putting the participants in danger of injury obviously) So you can prepare yourself should you ever need to use your training.