Flynn Rider is a manipulative liar, con-artist and a well-known wanted thief on the run, and was using Rapunzel for her crown for a decent chunk of the movie. Yes, Flynn, or rather Eugene warms up to Rapunzel, eventually, but his charming, feign- persona, is just heavily cringeworthy. With Aladdin, you know that he's just a boy that needs food to survive, and you know that he has a strong heart, he just feels like he's not worthy of anything. With Flynn, he's willing to use his charm, to use people, and almost does that to Rapunzel. It's just a bit, yikes.
Same with Nick. A manipulative liar, con-artist and uses his charm to manipulate others, is downright horrible towards Judy, and attempts to use her weaknesses and fears aganist her, so he can go back to his con way's.
Kristoff, while not much of a asshole as Flynn and Nick, still acts like a jerk towards Anna and her choices, while he's right, it's not within concern that she's going to marry a sociopath with a few days of knowing him; it's with a smug ' this girl is a idiot '. It's only after Anna has been cursed with a frozen heart, that he starts to be a nicer person and care about Anna's well-being, and safety. The day before, he could less, that a young eighteen-year-old girl was going to marry a dangerous psycho, that finds pleasure in decapitation.