A real life situation that I have seen at the game table was two people trying to remember a game rule and one of them was on the right track and starting to remember but the other guy helping him went down the wrong thinking trail and the guy about to solve it got all mixed up.
I've seen the same thing happen in just about every other real life skill check type situation from stealth to climbing, often with some real hilarious results.
But something in real life is totally misrepresented in the game rules.
The help action doesn't require a roll of any sort so it's always successful and never hinders the character being helped and that's just flat out wrong. Now I'm not saying it should be all the other way either. Plenty of times getting help...works great!
I just find it so crazy that something so common place is so.......unrealistic.
Would it really be so unfun if the strength 6 wizard couldn't offer the 20 strength barbarian much help in the way of lifting that gate up by hand? Wouldn't instead it be amazing to see him try so hard and badly that the barbarian found it more difficult to do because of the kind Wizards(Help)?
Well to be fair within the rules there are by RAW two limitations already in place:
The Gm must determine it is a situation where the task can benefit from help.
The helper must also be able to perform the task alone "attempt" is the word used in fact but a Gm is well within the RAW to say a character "attepmt" doesn't count if they have zero chance of success.
So your 6 str wizard might not be able to help the lifting at all, if it is beyond his weight lift rules etc.
Now to the "should" and "fun" "unfun" opinion parts...
i can always see places here or there where "more detail for this specific scene" could add variety and truthyness to a scene. As Gm i have no problem throwing that in case-by-case when it is obviously needed. Following the lead-in of their thieves tools examples, i have zero problem ruling uncommon task X requires proficiency and so that limits help as well.
As for the possibility of negative results, nothing stops the Gm from still providing the flavor fluff adder stuff if the "low die" was bad... so the advantaged 17 and 2 roll gets the success off the 17 but the Gm (or the player) can add in fun and cool flubs for the weaker helper **especially if it is a fish out of water** moment. (One of my rules is to not use these flub flavor fluff on a character's strengths - only their weaknesses.) The flub fluff should be cosmetic and trivial as far as any in game effects go... ripped pants... pratfall - or whatever the player enjoys....
i had a character once with a low str character who very often channeled the old Lost in Space Doctor Smith "oh the pain" back pulls and muscle strains after any actual physical activity.
I would not recommend the idea of putting in too many coded and locked in negatives mechanically because frankly i like the fact that cooperating is a very common place thing now instead of the everyone rolls - as it provides solid benefit for working togteher and keeping the best at the task involved - instead of see who rolls the better dice randomness.
Too many negatives and the cost-benefit goes away vs the roll-offs.
Still, some options the Gm could reasonably add in are:
1 "Lesser of two Goods": When advantage is rolled for skill checks, the "weaker" participant rolls the task with advantage, not the stronger. this means someone close to your skill can help, but someone much worse at this can actually hurt. bad folks searching can destroy clues and get in the way of a search, folks moving around trying to see can make noise that hides an approaching enemy.
2 "I just know." Require proficiency to help - period - without proficiency you are just not consistently trained enough to be able to smoothly work with others - you do your own thing and it works out but that doesn't let your raw talent work well with others. its an instinct and feel thing, not formal training.
Either of these IMO could serve a Gm well if he saw a need to put a little more focus on the skills and aptitudes of the second best characters at a given task and make having two folks decent at a thing a very well rewarded thing.