In any sport, team-building takes time. As divers, we are handicapped by the fact that we can't usually communicate our needs by speaking. When backpacking, if one person is walking too fast, the other can simply say, "Slow down." The buddy system usually only benefits the weaker teammate unless adequate training takes place to allow two individuals to work together in unison. The system is flawed in that respect, but fortunately, recreational diving is relatively safe. Since most of the "bad buddies" we meet come from times like you describe where two divers are partnered together temporarily, it often just isn't worth the time to fix issues and create a working team. Time has become a precious commodity and it does seem easier to invest this valuable resource in the joys of our own pursuits rather than endure the frustration and time required to create solid teams.