If the current finds a path through you, you're done. It does not necessarily have to go through your feet to the ground. Nor you you have to be barefoot and standing in a puddle. Quite often there's enough conductivity through your shoes to do it. This is why some work boots carry an electrical safety approval, and even that degrades as the boots age.
The other way you can meet your maker is if the current passes from one hand to the other. Let's suppose you have one hand touching the panel board, or maybe the sheath on a length of armoured cable, and you accidentally touch a hot conductor with the other hand. As the current passes from one hand to the other, it goes right through your ticker. Goodbye.