What games do you have a fondness for that, objectively, aren't really all that good?
For me, Grand Ages: Rome. Basic city building, straightforward resource management, and simple combat. Yet, each piece is just meaty enough and has just enough nice touches that the whole package works.
Resources are easy to manage, so the challenge for the economy derives from properly balancing long and short term goals and ensuring you don't neglect the necessities, including a military, rather than tedious and complicated finagling (looking at you, Dawn of Discovery/entire Anno series). The slave resource may also be the best (economic) depiction of slavery in a game: they aren't as productive as free citizens, but they require only a fraction of the space and upkeep. However, once you invest in slaves its very hard to switch over to free labor due to the space planning problems you will have inflicted upon your city and the need to keep the resources that the slaves produce flowing. Relying on slaves also means investing heavily in the acquisition of more (very necessary to counteract their inefficiency), meaning a large military and dedicating some of your (limited) trade routes to importing them.
The military aspect is simple, but the units have a fair amount of character. Elephants are awesome, but the gladiator slave legions are surprisingly endearing as you can declare them free, causing them to become briefly invincible before disbanding.
Finally, I love, love, love the character creation element: each mission you complete gets you a skill point, and points can be put towards two generic skill trees and one skill tree unique to your character's family. There are a lot of skills and they make a pretty large difference in how you play, and the extremely lengthy--frankly too lengthy, as you'll hit the level cap (which tops out at 30, I think) long before the end--campaign means that you'll get a chance to utilize a lot of them. It also nicely helps alleviate the problem of many city builders, where there's a fairly obvious optimal approach to the game that sucks a lot of the fun from the experience; here, your character choices can make pushing through the campaign & replaying the game an ever-changing experience. For example, one family specializes in slave labor, and maxing out their skill tree makes slaves as productive as citizens, increases slave income, and provides some handy military boosts (to help you get more slaves, of course!).
So, what game or games that are objectively kind of "meh" do you like? And try to keep in mind when a game was released; time has brought low many a game that was considered pretty good in its time.