There are definite categories of people, vis-à-vis whom, it is enjoined you may be good and do good, as Allah (SwT) loveth not the arrogant, the vainglorious:
''Serve Allah and join not any partners with Him; and do good to parents, kinsfolk, orphans, those in need, neighbours who are near, neighbours who are strangers, the companions by your side, the wayfarer (ye meet) and what your right hand possesses for Allah loveth not the arrogant, the vain glorious (Al Nisa: 36)
The essence of Islam is to serve Allah (SwT) and do good to fellow creatures, which includes animals, the service is not merely sentimental but practical as well, the rule holds, we may not assign any partners to Allah (SwT).
The categories of people vis-à-vis whom, it is enjoined you may be good and do good (alluding to do good in practical sense) encircles virtually everyone, we may come into contact with on a daily basis &/or frequently. It includes parents, kinsfolk, orphans, those in need, the neighbours who are near (alluding to neighbours who are located locally and with whom there is kinship as well) neighbours who are strangers (neighbours, with whom there is not otherwise a bond of kinship) the companions by your side (friends and associates in working sphere) the wayfarer you may meet in your sojourns (could be a casual acquaintance) and what your right hand possesses (what rightfully belongs to you, could be captives in Jihad, as per Quranic commentators). The wide list hardly leaves anyone; you may come into contact with on regular and casual basis.
Service deed may not turn into a show-off but it has to be done with all the humility in command. It is related that in our mutual needs we are all equal before Allah (SwT). Or, perhaps the best of us (as per worldly view) may be worse than the worst of us.