Toad differs from most other characters as he has had two personalities throughout the series. During the earlier bloopers, he has similar personalities with Squidward from Spongebob Squarepants. He was a grumpy deadpan snarker who loathed Mario and despised his life in the castle, often attempting to destroy it at any opportunity.
In later bloopers, Toad was portrayed as an insufferably obsessed fan of Mario, being annoying to the point that even Mario himself despised him to the point where he tried to murder him. He was overjoyed when Mario was captured by SMG3 and taken to the Kushroom Mingdom though, still showing his dislike for the plumber.
In Ssenmodnar 10, he was sick of being hated and mistreated by the other characters, with Steve even blowing his house up to bits during his president campaign. Wanting revenge, Toad disguised himself using a Majora's Mask replica and repeatedly went to the castle to harass Mario and the gang with many death threats. He eventually got Mario's old recipe for The Irresistible Golden Spaghetti and summoned the giant Mario Head, directing it to a collision course with the Earth in 20 minutes. Mario angrily chased him into Battlefield Bob-omb Battlefield, but upon arrival, 19 minutes have already passed. When Mario questions his motives, Toad reveals himself and lists the reasons, but Mario did not care any longer and proceeded to punch Toad into the Mario Head's nose.
More recently, the extent of Toad's life has shown him as an absolutely miserable person, after six tiresome years of putting up with Mario's stupidity and processing the increasingly retarded state of the Mushroom Kingdom have rendered him a hateful and pissy individual- not to mention that Peach apparently uses her Toad Retainers for humiliating and disgusting tasks in everyday life (including sponges, nightstands, and ladders). According to him, the only thing that makes him happy is seeing Mario and any other person he hates suffering.
As a form of relaxation, he began hoarding a massive stash of candy in the Metal Cap level; upon eating it, he gets a sugar rush and begins acting retarded and hyperactive, much to everyone else's annoyance. Unfortunately, he became addicted to the high and ate it nonstop, which at the last straw, lead Peach, SMG4, and Toadsworth to intervene. Although trying to defend it, SMG4 knocks him out and they send him to rehab, where he screams in horror at seeing Dr. Mario. However, whether rehab has been successful depends on bloopers.
Toad Gold and Stupid Mario Party reveal Toad to be an incredibly greedy person. In the former, after finding a cache of karat gold underground the castle grounds, he bought Peach's Castle and was violently protective of his wealth (he soon lost it after Luigi shot the floor and it all fell into the collapsing hole). In the latter, he used his friends to get money with the promise of giving the winner a Power Star. However, when Luigi won, Toad gave him a fake star and kept the real one for himself (granted Mario's noticing this led to him getting revenge on Toad by giving him a hanging wedgie on the Castle flagpole and melting down all his coins). The Mario Purge portrays him as being an even bigger coward than Bob, choosing to side with the Teletubbies to save his own skin.
He likes cookies (as do Bullies, Big Bullies and Lilyncookies), which results in him occasionally turning into Cookie Monster and going crazy.
He is addicted to sugar and becomes hyperactive when he ingests some.
He doesn't know how to use a lightsaber.
He once dressed like a woman to escape jail.
He drives a Cheep Cheep Kart in Retarded64: Stupid Mario Kart. Possibly this is a reference to the face he makes when he is using the Golden Mushroom power up.
In the blooper Spells n' Wiztards, it was revealed that Santa didn't give Toad his 2013 Christmas present, making him strongly hate Santa.
He has mushroom clones that look exactly like him. It's unknown if he used spores to produce them.
According to Mario, he's a little wiener. Toad also added that, in verbatim, "there's only 3 things that tub of flub cares about. Spaghetti, himself and being naked." in the episode SM64: Meet the Mario.
Toad appears to have a watch that says "Mario is my homeboy." Since this was during the period where he went through his personality change, it's possible that he removed the watch after going back to hating Mario.
Toad rarely changes his expressions. However, he's more prone to doing so in later videos.
Toad is one of the four characters to appear in the very first video by SMG4 (The Cake is a Lie). The others are Peach, Lakitu, and Mario.
He has tried to escape from Peach's Castle more than 643 times, only to be stopped by Mario in every attempt. He has been seen outside Peach's Castle however.
According to Toad, he gets paid by Peach in peanuts; additionally, Peach uses Toads for everything, including as a sponge and furniture. The worst thing Peach uses Toads for, however, is as a human body shield.
Toad and Toadsworth are some of the few Toads in Peach's Castle that are able to think as the others are brain dead.
He is a wizard and is able to turn invisible, teleport, and so on, at least in Mushrooms and Morons.
Toad goes crazy if he has coffee as well as sugar.
Currently Toadette is Toad's sister and NOT his Girlfriend..
Starting with Mario's Late!, a running gag in the series involved Toad sitting lazily on his couch while playing or reading on his phone.
Toad can be considered as a foil to Meggy. While Meggy enjoys going outside and having fun, Toad is shown to be a couch potato. While Meggy finds Mario's stupidity to be hilarious, Toad is aggravated by Mario's stupidity. And while Meggy and Mario are friends, Toad is happy to see Mario gone when he is briefly kidnapped in the Kushroom Mingdom.
His grumpy behavior in recent videos may be due to not eating candy anymore and he is forced to suffer Mario's retardedness putting him in a bad mood like he was before he started eating candy.