Recently I watched a powerboater run aground while steering for a waypoint straight ahead down a channel. He had his GPS on and was using the "go to" function to steer to a waypoint ahead, which gave him an arrow on his device that pointed to the waypoint. But he was blithely unaware of a side current that was gradually sweeping him sideways out of the channel. Eyes alternating between the arrow on his GPS and a point ahead, toward which he faithfully steered, he had no inkling he had left the channel until his boat ground to a halt on a sandbar. Luckily for him it was a soft grounding and he was able to get off, but it could have been rocks tearing a hole in his bottom. Here's an article on how to compensate for currents (or leeway in a sailboat) to ensure you safely reach your destination.