Evergetism, to sum it up, was a constant of the Hellenistic world and the Roman Empire.
It's basically giving to a city something (a building, for instance), for show your munificience and your liberalities. Some of it was done for political reasons (like offering circus games to quell the mob), but a lot of it was not done for such obvious reasons. It could be also much more down to earth, like accepting to provide the gymnasius of your backwater town with olive oil for the athletes.
In a book I reread recently, they give the case of a tiny Aetolian city, Kryterion (sic), who had lost her walls. Kryterion send ambassadors around the Med to ask for money for new walls, and rather amazingly, she got signficiant money from the Lagides, the Antigonids, Pergame, Rhodos, and the Seleucids. I say amazingly, but it's amazing for us. It was not amazing for various polis who frequently asked-and got-subsisidies for building projects. Most of the well known Greek monuments, especially theaters, were paid by Hellenistic kings.
So, according to you, fellow Paradoxians, what was the motivation to make such generous donations to insiginifiant targets ? Pride ? Social norms ?