like most people who post here you need to read Paul Graham's early work. professionalism is harmful to quality of work and especially so in startups. professionalism is an artifact of the industrial revolution and is not relevant in all fields. computer programming is to some degree post-industrial and professionalism is irrelevant and archaic for many programmers. criticizing a programmer for being unprofessional is like criticizing him or her for not being well acquainted with the phases of the moon and the effect those phases have on that programmer's crops.