Hey all I have been part of a band the three original members ( myself included) are childhood best friends. We are an all original band that used to be fully instrumental but just a year ago added a singer who had some songs written (lyrics only). We have been extensively composing and working on these songs soon to be released as the first debut album under this new line up. We meet up twice weekly at the guitar player's house we have set up a really good soundproofed space that has become our studio as well. Every now and then and when the drummer cannot make it to one of the two rehearsals the guitar player invites a drummer or a keyboards player to jam and stay fresh. This doesnt happen that often though cause we usually meet without the drummer to write songs and work on the passages . (the drummer myself and the guitar player compose everything including the vocal lines sometimes it is a collaborative effort, with sometimes either me or the guitarists writing entire songs) I digress. Out of the blue the guitarist calls me up to tell me that he has invited a friend of his over to our first meeting this week. His friend is a bass player and according to the guitarist 'he will be there to assist'. Sounds weird and wrong on so many levels. I did ask assist with what and how but i got a simplistic answer that he can give his input into the song we are currently working on. Mind you i am on great terms with my band mates they commend my professionalism and both my rhythmic and songwriting abilities and creating a very tight pocket with the drummer when needed and soloing and playing lead when needed. Only thing i dont do well is play with a plectrum. I checked out this friend and he is into cover songs and played in cover bands and his thing happens to be metalcore/djent stuff. I have classical training (classical piano for 10 years before switching to bass in 2000) and have been studying jazz. I listen to a lot of metal bands as well as many different genres (Funk, inde rock, hip hop, electronica, jazz and its subgenres of course). I felt offended that he didnt ask me before inviting him over and threatened that some guy will be there with his gear (maybe) or worse going to be using mine ( and i hate to give my stuff let alone my gear to anyone to play it) . Any advice, did this ever happen to anyone ?