Your vehicle is home to many mechanical systems, and the automatic transmission is one of the most complex. It's also one of the most hardworking since it is constantly controlling the way power is directed from the engine to the driveshaft. As such, it needs to put up with a lot of wear and tear, and that means problems can develop over time, including delayed shifting.
Otherwise known as 'delayed engagement', delayed shifting occurs when your vehicle pauses either before shifting into drive or when gears are changed as you drive.