Heroes who have moments where they have shown to deviate from their heroic moments to either do no heroic deeds or to do the opposite. These heroes have moments where they "heat up" and act differently than they normally would act. These moments are normally short and the hero returns to doing good for others.

Examples include:

1. A hero who fell into despair and lose their hope because of losing their loved ones, being betrayed, being defeated or failed, having personal issues or they were being looked down by others. Usually, the hero would became hostile and refused to do anything optimistic as they would rather give up instead of standing up who they are. Sometimes, the hero would break into tears and lamenting on their problems. Under these circumstances, the hero would prefer to be alone and stay away from others. After the moments, the hero would come to get over their depression and go back to helping others (e.g. Blossom from the 2016 reboot, Nightfall, Gon Freecss, Luke Skywalker, Shrek, Catra, Ethyl Countrisyde, Wolverine from the X-Men Movies and the reboot version of Scrooge McDuck). In these circumstances, the hero also temporarily lose control and seek revenge. However, they managed to regained their sanity and mercifully spared others' lives for good. Some heroes can be nihilistic in some cases (e.g. Count Bleck and the DCEU version of Wonder Woman).
2. The hero becomes hostile and has moments of being a jerk to others. This may be because they are insecure, being persuaded by others with bad influence, being annoyed, unintentionally doing it so, or going through a phase in their character. In these moments, the hero would break out of this mentality and apologize to those whom they offended. In other moments, the heroes would learn from their behavior and not to repeat it. (e.g. Arthur Morgan, Batman, Buttercup from the anime series, Donald Duck, Katsuki Bakugo, Ultraseven, Sony's Marvel Universe Eddie Brock, Felonious Gru, Gary Goodspeed, Gumball Watterson, MCU version of Iron Man, Lance Sterling, Mace Windu, Midna, Motomo, Rainbow Dash, Raphael from the 2012 series, Raven, Revali, Red Circle, Scott Wozniak, Severus Snape, Thomas the Tank Engine, Toph Beifong, and Vegeta)
3. The hero would lose their temper and get angry with others, mostly for good reasons. It is mainly because of something that irritates them, anyone making mistakes, getting into arguments, being deceived, others being jerks or someone harming their loved ones. However, the hero managed to calm down instantly and apologized for their behavior (e.g. Anger, Buttercup from the 2016 reboot, SMG4, Falco Lombardi, Beep-0, Zuko, NostalgiaSquare, DreamWorks version of God, Merida and Saitama). Sometimes, the hero would never apologize, if it's well-reasoned.
4. The hero would make mistakes which unintentionally caused problems with others. The reasons for this include mischief, carelessness and somewhat doing reckless things without consent. Despite this, the hero would fix their mistakes and not to repeat it again (e.g. Capper, Jimmy Neutron, Tommy Jarvis, Mordin Solus, and Bing Bong).
5. The hero was exposed to toxins or forces that brought out their darkest qualities or something even worse. The heroes under these instances were either possessed, corrupted or brainwashed from an external source. However, the heroes managed to recover themselves (e.g. Jak, Paper Bowser, Sasuke Uchiha, Zero, and Steven Universe).
6. The hero could temporarily ally with villains for their good intentions, on undercover, pragmatic reasons, or being manipulated by them for their own gains. However, the heroes would eventually realize it and rebelled against them for this (e.g. Mr. Snake, The Chosen One, Raven Branwen, Riku, Shadow the Hedgehog, Conker the Squirrel and Knuckles the Echidna).
7. The hero can have a mental breakdown or a tantrum, such as anxiety, depression, or worse, losing control of themselves. However, they managed to get over with it (e.g. Bubbles from the 2016 reboot, Cho Sang-woo, Patrick Star, Saiko Bichitaru, MCU version of Star-Lord, Rabbid Peach, MonsterVerse Godzilla, the MCU version of Wolverine, Jack-Jack Parr, and Sylvia Turfora).
8. The hero who has moments of antagonizing others for any reasons, including for good. However, they later reformed themselves and apologized for their actions, sometimes they didn't apologize even if it's well-reasoned (e.g. Bowser, Sage, Rabbid Mario, Scar, Donkey Kong, Satsuki Kiryuin, and Tatasia Offentus).

This is an opposite of Inconsistently Heinous with Cooling-Off Periods and a brighter counterpart of On & Off heroes.

NOTE: This category is different from On & Off because they are switching sides or committing villainous deeds from time to time while Inconsistently Admirable with Heating-Up Periods have significant amount of time where they are acting differently than doing heroic moments or did nothing heroic at all.