Teammates need help to choose to belong. When I first join a team, I am looking closely to how everyone behaves so that I can assimilate into the culture as best I can. Training is a great jumpstart to that process. Leaving a new teammate to “figure it out” like the rest of us is just mean. Refusing to train new people dooms them to make all the same mistakes the team already found solutions for. Don’t be lame…provide training and make new mistakes.