At the end of the day, the NFL is a job. On a job you're paid & expected to do a job and get along with and sometimes help your 'co-workers'.
Now in Flacco's case we don't know what was said to him behind closed doors. If the coaches said 'hey, we want you help out and show veteran leadership to Lock'....then Flacco's gotta do it ( it might be a part of why he was brought in).
Bottom line, Flacco has got to understand that he is probably not the Qb of the future. So he should win and keep a good attitude, thus
setting himself up for another NFL oppy. in the future.