There are two reason why you can’t speak lashon hara about someone who has bad character traits, whether it is anger, haughtiness, etc. (1) Either because he might have felt bad and repented after he expressed his bad character like acting out of anger or (2) even if he clearly doesn’t regret the way he act and you see him act in the negative way all the time it’s possible he doesn’t realize the severity of the problem. There are so many complex variables who, when what, where of how to deal with ones feelings that they are very hard to control, also people who are even Torah observant don’t realize how important it is to constantly be working on our character therefore there is no excuse to speak Lisbon hara about a person who you see with character flaws. Even when the Gemara in Tania 7a says one is allowed to call a person who is brazen and chutzpadik, a bad person, that is only for that bad trait but even then you can’t be so quick to judge who has chutzpah and can be called bad because you have to first fully understand the problem of having chutzpah and delineate whether that person has enough chutzpah if any to be called a bad person. There is one other gray area, a trait which really isn’t bad but other people might take it negatively or might start to talk badly of the guy based on what you said. For example being strict is not a bad attribute, we find that Beis Shammai was stricter for the sake of the honor of Torah than Beis Hillel was. That does not mean they were wrong they just had a different outlook in life of how to act. See also Rav Yisrael Salanter’s letter 28 in Ohr Yisrael about this concept. So to call a person strict is not lashon hara unless stated in a negative context. However one should be careful who they speak to when they say someone is strict because it might be placing a stumbling block before the blind for someone might say, ‘you know him now but I remember him when he had terrible anger management problems’ so depending on who you talk to what you say might lead to lashon hara so you have to be careful, just like you have to be careful in front of whine you praise others because the listeners might start talking lashon hara about who you praise. It’s never good to overly praise someone because it will prompt others to find faults on that person.