These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Base Breaker: The move from UEP Systems (who developed the first two games) to Idol Systems/989 Studios beginning with 3. The latter entries focused less on the tricks and stages, and more on ridiculous hip-hop characters, gimmicks, Product Placement of various products and namedropping real-life pro snowboarders who could be unlocked and played against in-game. On the other hand, there are players who enjoy the latter installments more due to greater gameplay variety and more courses, while disregarding the earlier entries for being buggy and limited in scope.
Character Tiers: All of the games have this in the form of various skill meters (Stability, Handling, Speed, Acceleration).
In 2, Irin and Cindy are generally considered lower-tier because of their average skills. Yaggi (good stats in all fields, great stunt skill), Jin (high speed, lousy everything else) and the Alien (insane stunts, terrible speed) are considered High Tier, and the unlockable Boss (every skill maxed) and Joke Character Snowman (great stats all around) are considered God Tier.
A well-known bug in 2 allows the player to turn their board around in the training course by hopping, and going off a ramp backwards launches the character hundreds of feet in the air, allowing them to execute insane tricks.
In 2 and 3, the player can rack up insane Combos on qualifying jumps by holding the crouch button and a directional key while mashing buttons, causing the characters to do all sorts of insane tricks.
Most Annoying Sound: The pounding heartbeat during the jump sections (especially when you have to continually replay them to qualify) and several of the announcer's comments during the races.
"Not bad...but you could do a whole lot better!" after every jump in the first game.
THE CHECKPOINT IS COMING UP!YOU BETTER HURRY!!!
(when the player makes a mistake) What are you doing!?!
Seinfeld Is Unfunny: Cool Boarders was the first video game franchise based on snowboarding, and paved the way for series like 1080 Snowboarding, Amped and SSX to dominate the market. Compared to those games (which go much further with the "extreme snowboarding" mantra), Cool Boarders looks downright quaint, especially because it plays much slower and has a much more simple interface and gameplay style. The original game in particular gets this treatment - it was a glorified demo and a buggy mess that only had three tracks, five boards and no competition mode, but it laid the foundation for every snowboarding game that followed it.
Sequel Displacement: 2 is generally considered the "true" start of the franchise, as it introduced many of the elements that would define later games (such as the Competition and Mirror modes, multiple secret characters and the training courses). In addition, several of the opening levels in 2 use large sections of the stages from the original game, but with more room to maneuver.
Sequelitis: The franchise appeared to be turning into this, as at least one installment was being released every year (Cool Boarders 2001) along with at least one portable game. This practice ended due to a combination of competing franchises becoming much more popular, the original developer (UEP Systems) going under and the series never fully transitioning to the Playstation 2.
Surprisingly Improved Sequel: Both 2 and 3. The third game, in particular, added many more characters (both normal and hidden), different challenge modes for each track, better graphics, fixed hit detection, difficulty levels, more tricks, boards and the ability to go split-screen for two-player matches.
"Avalanche" in 3. You have a limited window of time to make it to the end, there are giant snowballs that can (and will) hit you on the way down, if you slow down too much you get insta-killed by the onrush of snow, and you instantly fail the level 2/3'rds of the way through if you miss a required jump that's on the left side of the stage.
Urban Legend of Zelda: Every installment has had at least one rumor of an ultra-powerful board/character that can only be unlocked by doing insane feats, and were proven to be fake:
The original game had the mythical "Hybrid" board (supposedly the best in the game) that would be unlocked for beating every best level time and getting the highest scores on every stage.
It was rumored at the time of 2's release that a red variant of the unlockable "Alien" character could be acquired if the player achieved a 45.0 or higher on the Halfpipe. People who have actually aced the half-pipe with a perfect score (meaning nailing every trick and getting every variation) have never unlocked any such character.
It was rumored in magazines that there were ways to unlock three CPU-controlled characters (Kelly, Jicchi and Nick) by doing things like beating every stage's time and score. They cannot be accessed by normal means (even though they have voice files and are included in the U.S./European opening movie, suggesting they were Dummied Out), and only exist to fill out the challenger roster during Competition mode.