Let's concentrate on the Gossip part for today. It's part of the business - agents, casting directors, directors, producers and mangers do it. Actors do it, too.
Just be careful if you choose to gossip that it doesn't do you in. I've seen agents, casting directors and managers at industry events behave scandalously - especially after a few free drinks. And what do they blab about? Actors. Don't add fuel to their fire. I had the recent unpleasant experience of being on a six-hour flight sitting next to a manager from a well-known agency who took advantage of the time to rip apart almost every model in his agency. The casting director beside him knew a couple of the models he was raking over the coals. Two things become apparent here: 1) the manager shouldn't be so unprofessional as to behave this way, but you can only control your own actions -- not those of other people; and 2) the models who were included in the tirade shouldn't have behaved in a such poor manner in the past to give the manager, or anyone, for that matter, ammunition to be shot with.
Moral of the story: Don't Make Enemies! Don't badmouth anyone! Tough to do in this business. Zip the lip. You don't know who can help you and who can hurt you - we all wear many hats in this business. The person being trashed today could be the agent two years from now who decides to take a pass on representing someone. Or one day the actor walks in an audition room and there they are, now the casting director. Memories are long. More people know you than you know them - and they know a lot about you. Bridges once burned here are permanent. There is never a kiss-and-make-up. If something bad is said about someone it is almost guaranteed that that person will hear about it, including the source. This can be why phone calls and emails can start to fall off or a career never proceeds past doing background work. One photographer made an astute observation: "We don't have to eliminate actors, they eliminate themselves." If this doesn't make a talent paranoid, I don't know what will!
I've heard coaches tell stories about the actors under their tuteledge. Frequently they are bragging on a stellar performer, but sometimes they are just venting frustration with an actor unwilling to be fully prepared or who crossing the professional life and shares too much personal information not pertaining to the coaching experience. Who are they sharing that with? Other actors, agent and manager acquaintances, or worse, maybe casting directors!
If you want to vent, that's what therapists are for . . . although a good jog in the park might be healthier, not to mention cheaper!
The bottom line is that sharing positive experiences is better for everyone's emotional, mental, and long term well being. Avoiding being the gossip, promoting the gossip, or being the subject of gossip due to a poor choice is in every entertainer's best interest!