Did any slaves get treated well at all? Are there any examples?

Yes obviously, a fucked up dream neither the less but I'm sure stuff like that happened.

Or a poor sociopath, who is statically more likely to do those things?

Depends on how widespread slavery is and who is being enslaved.
A greek slave in roman employ with a modicum of education was not likely to go to the mines. You'd teach or perform administrative work, sometimes you'd even be paid a wage.
Ottoman slaves usually did alright once you got past the whole some get castrated bit, mostly because slaves were more for domestic labour and administrative functions than proper labour, agricultural and industrial slave labour. Those are the ones that get folks dead.

Wrong. Have fun dissolving into Hades when you die though.

Family slaves were treated decently. Latifundium slaves, however... That's a whole other story.

Depends on times and the slave job. Physical work slaves always were treated horribly especially if it was a job no sane man wanted to do. More educated slaves usually got treated better. Servants too got decent care. Not that being a slave was even then some heaven on earth, being a slave still meant you basically were working 24h to someone with little freedom to refuse to work. It just wasnt complete shit and possible a better option than not being a slave, for example being a peasant could have been even worse of a fate.

Not all work slaves were treated poorly. It was mostly the ones that worked in the mines or on the latisfundium that lived a life of stereotypical thralldom. Ofc a slave, even if treated 'not poorly' was still treated in a different way than a freeman or even a freedman. The big thing to take home with roman and hellenic slavery is that it wasn't neccessarily an end stage in the slaves' life. Alot of them could reasonably expect to eventually either be freed by their master or afford to buy their own freedom. In the roman world, you would then become a client of your former master, which was handy as it could help you to kickstart your own enterprise. A crafty slaveholder would, in other words, have an incentive to treat his slaves farily or even kindly, and provide the clever ones with an education of sorts, as it could mean lucrative business down the line.

However, one shouldn't forget that the punishment for slaves were extremely draconian. The most famous example is that if one slave killed his/her master then all of the master's slaves would be put to death. This law was the source of a scandal in Rome during Nero's rule when one universally hated and disdained person was killed by one of his slaves. Since the man was wealthy and own many slaves 400 lives would have to suffer the death penalty for the action of one man. The thought of this happening shocked and horrified the citizenry who demanded that the law would be revoked. Nero, or rather his 'ministers', argued that the safety of every slaveholder relied on that law and thus refused to remove the law.
Another roman law pertaining to slaves ordained that a slave couldn't legally testify without being first tortured.

Ofcourse some were. Slaves had a variety of different tasks like workers today. Some cleaned the toilets or worked in the mines while others had comfy office jobs.

I read somewhere that Roman slaves were treated like furniture rather than livestock or people.
Dunno if it's true or not

More educated slaves like Greeks who'd teach their master's kids philosophy and rhetoric lived pretty comfy.

In Rome there was always a possibility for a slave to be freed if their master liked them enough. Cicero's secretary Tiro was a freed slave.

en.wikipedia.org/wiki/Marcus_Tullius_Tiro
That's Varro's quote and he writes in a specific context regarding agriculture. Slaves were looked on as members of (extended) familia.

In the sense that they were a status item, roughly comparable to todays tech gadgets.
The really rich people who liked to flaunt their wealth had slaves that only did one thing in the house.