I've learned through experience that I can listen to loud, intense music while taking pictures or thinking of ideas for photographs, but I should listen to soothing music while developing film. Once while developing a roll of film and listening to Trans Siberian Orchestra's Wizards in Winter, I got too vigorous with the agitation and ended up with with high contrast negs. Using Rodinal 1:25 for the first time didnt help much with contrast control, either