No, for two reasons:
1) Adventures are designed largely expecting that the bad guys are going to go down, and the challenges overcome. If the PCs do that a little more quickly than expected, that's not a big deal to the game overall.
2) Success and failure are not, psychologically speaking, merely mirror images. Especially when the player has built a PC to be competent at a thing, and critical failures assail in that area of competence.
1) And if they do it more slowly, also not a big deal--in fact, it has more tension and makes the game more challenging.
2) Really? Are you a trained and accredited psychologist? I never said they were mirror images. Failure is actually more vital to most people than success. We learn more from failure. Often when people reach a goal and succeed it feels anti-climatic. Bad luck is a humbling experience to those who are very competent.
Anyway, it is a moot point however because what makes a game appealing, psychologically speaking, is the level of the challenge to an individual. Consider a game, such as golf. Bad shots happen often (even to professionals), and they are frustrating of course, but they are part of what makes the game what it is.
"I have fun with it" is not really an argument that it is a good idea in a general sense - anecdote is not data.
No, it isn't "data" but it is perfectly fine for a discussion. People often as about a certain thing in the game (such as the thread about playing all the same class or which of three monks is most fun) and offering anecdotal information is perfectly valid.
Every person who is complaining and such about critical fumbles is also offering anecdotal information, FWIW.
Some people play heavily PvP games, and have done so for decades, and find it adds to the game. I would have a hard time recommending it as a general practice, though.
If they are asking it about it though, you can certain recommend it or not as you see fit.
See (1), as the monster is mostly there to be beaten. Also see (2) above, as the GM doesn't usually have a year's worth of thought and investment in any particular monster. If an otyugh has a critical fumble and... dies swallowing its own tentacle or something, the GM is not going to be broken up over it. In general, the psychological position of GM is not the same as a player, so the impact of failure is significantly different.
The concept that the monster is there to be beaten is part of why D&D is too easy IMO. And as a DM, I put several hours each session into it, and that includes selecting opponents, etc. My investment, especially in the BBEGs for my games, far exceeds the time most players IME put into their PCs. I know
some players really get into backstory, developing personality and such, but that is few and far between IME and when I do see it, sure they do it over the course of months or years--but it is maybe 30 minutes of thought a week on it (if that). It isn't as though they are toiling daily or weekly over the decisions about their PCs. YMMV of course.
The degree of critical fumbles is a larger issue IMO. Sure, in the 80's, you could stab yourself in the heart by accidentally falling on your blade when you attacked, but you could also cut off a dragon's head if you rolled well enough. The mishaps, and even "disasters", I am discussing and most tables use (IME anyway) is hardly of that caliber anymore.
In short, there is nothing wrong with using critical fumbles if you implement them well. They add both tension to the game and can offer comedic relief at times (especially when the result is not something that leads to a PC's death--which it shouldn't in and of itself). Once I had a player whose cleric used a sling. He ended up with a disaster for his fumble and his sling slipped out of his grasp and ended up in their campfire--at which point is was quickly burnt up. Nearly twenty years later, another player and I still joke about it. It was funny.
