When it all gets too much go to the freezer take two ice cubes place in a glass pour in a generous measure of Scotland's greatest contribution to human wellbeing (it must be at least a 20 year old single malt), put on a relaxing CD and enjoy. It won't make you a better guitar player but it's less expensive than slamming your guitar into your amp, trouble is I always forget to get back to practising when I'm in an advanced state of relaxation !