I'd imagine that the problem you're noticing with this cartoon is that you were being too formulaic in writing it. Prior to this, all of your work struck me as much more natural and genuine in terms of humor, almost as though you were sprinkling them with jokes that you had made during exchanges you had with friends of yours in Skype calls, which gave them that extra vitality that people have come to appreciate in internet cartoons.
I'm privy of the fact that you hold yourself and what you do to much more scrutiny than other cartoon men and women of the interwebs and while I think that's commendable in that it's exhausting how many internet animators approach their work with passivity, I think that it's a bit of a Goldilocks effect between too LOLFARTS uncaring and too calculated that should be juggled. This kind of mentality is appropriate when implementing a series and taking into account all of the nuances inherently associated with that undertaking, though, when it comes to individual shorts like this one, it just comes off as awkward and anemic. I feel that this kind of mindset toward production of internet cartoons is rendering the whole NG/YouTube animation scene into a diluted form of Hollywood (only with talented dudes frittering away months of their time scratching at their cintiqs in a dark room without pants on rather than soulless conglomerates hiring a plethora of people to miserably contribute their individual dash of icing to the cake). It seems that, as this quest for excellence in internet cartoons continues, people are losing sight of the novelty that caused them to deviate from that of televised cartoons. There's an energy to incorporating what you would genuinely consider funny into your work that can't be captured by going about it with an "am I funnying right?" upbringing.
Of course, all that I've ranted about here is entirely subjective and by no means concrete. Outside of, perhaps, the delivery of the final joke (as in, the conveyance of it, rather than whether or not it's funny), I'd opine that you nailed this cartoon on a fundamental level. I just felt compelled to vomit my musings through my keyboard after having listened to you rant about your loathing of this cartoon on Sleepycast 23, recalling your twitter rants that you went off on around the time that you were animating it about your premonitions of the audience hating it and finding that you posted it to newgrounds 2 months ago after querying it on Google to give it another watch. I'd completely agree with JohnnyUtah's claim that you're being too self deprecating about this, by the way. It's understandably frustrating to make something that doesn't collate with your own views on a subjective level, but, you put a lot of work into this that's very much evident in the finished product. The animation here is fluid and professional-looking, your expressions are spot on in their over-the-topness and the pacing here was really nice too.
Anyway, just my thoughts. Can't wait for Hellbenders, by the way. Keep on keepin' on, Mr. Pebbles.