Our voice does that in smaller spaces, so I guess your bathroom is medyo small? Yeah I think it does that because in a smaller space, the sound echoes more and it bounces all around the room. Meanwhile in a bigger space like an church, it fades after the second bounce because it's too far. Gets? Am I making it more confusing? Sorry. Basta its's like that--that's why you need microphones more in churches and open areas than in your bathroom or in your closet.
The sound wave bounces back instead of being absorbed by the walls.