Pilots try as much as possible to perform rolling takeoffs, which is a takeoff performed without the aircraft stopping once it enters the active runway. The main advantage of this is to reduce the risk of foreign object debris (FOD) ingestion into the engines, where the risk of doing so is greatest if the aircraft is stationary and thrust above idle is applied. Another reason for doing so would be when air traffic control clears you for an immediate takeoff – possibly due to landing traffic not far behind you. You’d want to get airborne and rolling as quickly as possible, or the guy behind you would have to go around. Here’s a great video of that happening with full ATC recordings – credit to SiVideo Aviation for the fantastic video: