Let's start with why a couple thought it would be a good idea to give each of their identical twin sons the same name, do the same with the likewise identical pair of slave boys they just bought, and carry on from there.
Even more frustrating is the fact that even though Antipholus of Syracuse not only knows he has a long-lost identical twin brother but has been actively looking for him for five years, he can't figure out why everyone in Ephesus seems to know who he is!
Both Antipholuses are ready and willing to beat their servants (or the men they believe are their servants) when they're even the slightest bit annoyed with them, which was relatively acceptable and funny at the time they were written but is very uncomfortable to modern eyes. Today productions often try to decrease the awkwardness by letting the Dromios give as good as they get when it comes to blows.
Also, nobody bats an eye at the fact that Antipholus of Ephesus goes to visit a courtesan, even on the off-chance that sex didn't ensue.