Mature team members:
- Don't complain about "too many" meetings but help improve efficiency & communication to reduce the number of meetings.
- Don't play with their phones in meetings, but interact.
- Don't feel embarrassed or under-qualified to question and correct other team members, even more senior team members.
- Don't get offended or hurt when corrected by another member.
- Don't get hung up on team hierarchy. We're all just developers.
- Help and support each other. There is no point in individual success. There's no place for selfish behavior in a team. The product/company doesn't benefit if the team isn't working together.
- Don't complain when asked for help. If you're the guy who always says "I've got my own work to do" then don't expect others to help you next time. I always remember this Ace of Base line from my school days: "To help another person will make you feel important". It's satisfying to help someone and a good learning experience on top of that. There is no better way to learn than to teach.
- Have a sense of humor! Don't take things too seriously. We might as well try to have fun while we're doing this.
At a previous company, all teams had names. X-Men character names like Cyclops, Havok, Wolverine, etc. So when I started at my present company, I suggested giving the teams names. It wasn't a popular suggestion :-) Apparently I was the only one who thought that giving teams names like that was a 'fun' idea. Of course, that's perfectly fine, I just had to realize that this team has a different idea of what's fun than I did.