Three things I have no technical knowledge of...
1. My daughters IPod, I have never downloaded a song. Streaming my favourite radio station is good enough for me.
2. Upgrading/repairing my computer, it isn't doing what I want... restart usually solves my problems.
3. Electricity... amps, volts so on and so forth... what the

is the difference? Its all electricity isn't it?
Three things you have done but wished later you hadn't.