It always amazes me how good sound makes difference in the movie. It plays nearly the main role at least for me. It can be explained by the fact that the picture only effects us visually,  maybe emotionally, but the music and sounds make an impact on almost unconscious level of our  brains, hearts and souls. If the sound is good you will never notice it, you just know-it's ok, but if the sound is bad no matter what your film is about and how charismatic your character is the audience will always react -"smth was wrong, but I don't know what" or "I like this film, but smth was off" etc. I really enjoy my pro tools class, but the more I learn the more I understand that sound mix should be done by professionals in special facilities because  that's where the magic happens- couple of ambience tracks, reverb here and there, EQ adjustments and five hundred different audio clips from different days, places and recordings will marry together and become a beautiful piece. I wish I could do it by myself one day... (Pro tools station at SVA NYC)