What are some things that Reeve's Superman did that were played up for humor at the time that now looking back are kind of "ehhhh, that's character assassination?"

For me (this is probably my biggest gripe with Superman IV among many other things) it's them having him two-timing with both Lois (who he tries to date as Superman) AND Lacy Warfield (who he's dating as Clark Kent) in the film. Them devoting an entire drawn out scene of him actually trying to score a double date with Lois, Lacy, and Clark Kent/Superman and switching back and forth between both identities constantly was just too much.