If you're always busy, having a shower is probably the only time that you're ever alone and you have one thing in mind, you're going to smash it like you were playing at the O2 arena. The shower brings out your inner diva and because you can hear the sound of the water running, you're convinced that this noise will be able to block out the sound of you singing, so your audience (neighbours) won't be able to hear you. However, this is never the case and they'll probably have a little giggle at you practising your best Elvis impression.