The only time this was ever an issue for me was
9. Reply 1988. I think it was because I was offended by the writers and director pulling a fast one in the "20 years later" interviews we saw as early as episode one, in which they gave the husband of Sung Deok the sarcastic personality of Jung Hwan, but we finally learn it's Taek. Boo, writers. Not to mention Sung Deok had so much more chemistry with Jung Hwan, rather than the barely functional Taek. Back when they were in their 20s, she couldn't even have a normal conversation with Taek, for Pete's sake.