A Roman woman or slave would probably be very happy with their freedom.
Romans will appreciate many forms of entertainment (such as sports, movies, sex industry) but are very confused about the fact that they are all free people.(not the sex industry).
Roman men will find our society very feminine and can not understand anything about the Treaty of Versailles, to name 1.(Cooperate with other peoples? What? Genocide is a crime against humanity and not the right of the strongest?)
The evolution in terms of communication, transport, mechanisation.Access to information, medication that cures deadly diseases, too much to mention. The increased daily comfort (ever though the wax done by hand, ever traveled in a cart without rubber tires?): Brilliantly they would find it. The crowds would not seem so uncommon for a resident of Rome.
What they would look forward to is the pollution, the nonchalance with which modern man’s environment helps the destruction, the stench that we no longer smell, the noise, the increased pace, the ability to destroy the Earth.
Without a doubt, they would wonder how all those people, who work in the explosively grown service sector, deserve the cost and where their food (which would not taste them) come from their tangible goods.
If they have the choice to turn back to their era or live in our time, I think a large majority chooses to take their chances here.
A Roman from the first century would miss things like Garum, a salty fish sauce that was used like ketchup now. Malaysian fish sauce would probably be an acceptable alternative.The violent gladiator games in the Colosseum would also be missed; It is questionable whether football or boxing would be sufficient.
Romans would be amazed by the lack of temples and gods.They would probably be afraid that the Roman gods, especially the main god Jupiter, are neglected.
The calendar would also be enigmatic.Not only were the day names different, but also the months and there were only 10. Although Julius Ceasar changed that, but it was not common practice.
Roman Elite would miss slaves and find the idea to pay a servant or house assistance not very attractive instead of just hitting him.To a large extent the Roman economy was dependent on slaves, and many slaves had skilled work, their own money or even property. Poor Romans would probably be relieved not to have to sell their children to survive.
Our Roman visitors would not like toilet paper.They would find the nasty and not very purifying. Romans used moist sponges to clean themselves; They also had running water and loved their baths very much. Those baths were not only to keep you clean, but also an important place for social contacts and gossip.
Upright at the table to eat would also be somewhat odd, as well as the sheer amount of food from other cultures, which we very simply find.Think especially of all the food of Columbus that the Romans would not know: tomatoes (pizza!), potatoes, salmon, pumpkin, peanuts, corn, vanilla, berries, chili,…
Romans would find all that fuss about LGBT ridiculous, as well as most western morality.We should explain to them that gay sex with boys in our world is no longer allowed, thank God.
The Romans would love that there was land discovered over the sea as they knew it.They would probably make their ships ready and go on their way to conquer America.
They would also love electricity once they had ovr their fear; They were crazy about toys, especially if they could move.They would feel at home on the Internet as fish in the water.
Some things would be the same then and now.Romans loved their children, talked gladly about politics (politicians were as reliable as nowadays), and were keen to meet.
Thanks to Adrienne who forced me to read this carefully.