Sometimes it can be really hard to judge how "good" one's own art is. It's easy to turn blind to art one creates (one stares at the damn thing long enough, after all). Sometimes things look good to you - and not to anyone else. And occationally there are those images that you yourself were not particularly happy with but that others like a lot. It's all subjective of course, but sometimes this can be really surprising. Tell us your anecdotes in this thread.
Below are a few of my own pickings:

Hard to imagine that
Party of Trolls is more than seven years old now. This image was intended as a total throw-away. I started drawing a random woman, then made her lit by green light, which ended up looking just like green skin, and to fix that I eventually just messed around and converted her into a troll. I was not at all pleased with the result - the cropping of the image is horrible, the legs are off and overall it's not really a finished image.
But a lot of people liked this one. A lot, no matter how much I tried to downgrade it. To this day the troll girl is a favourite character among several of my relatives and they are the main reason I make new images of her now and then. I eventually did an
updated version] which at least made use of the entire canvas.

It's a sketch. Really, it is. I made
Grumpy farmer as a tutorial piece for how to sketch characters in GIMP (the tutorial's in my sig). But for some reason this image gets mentioned and pointed out when RL people sift through my gallery. I still don't really know why.

I remember being awfully proud of this.
Much deserved break is a fan-art piece of sorts for the MMORPG EVE online (I ran a small art collective inside the game at one point). People were not too pleased with it though and RL friends were most sceptical, notably with the anatomy ("stiffness") of the guy and a faint uneasiness from the slope of the horizon. I didn't really buy the anatomy critique at the time but with the benefit of letting it rest for many years I can see the point. It's just not as good as I thought at the time.
The Warlord was, at the time, my largest project by far, it took more than a week to complete. It's also accompanied by a massive tutorial. People had good things to say, but I must admit I was never quite pleased with the final outcome, even less so as time has passed. The two characters feel too stiff and impersonal and the image feels to barren to me. In the end this came out more as a technical exercise than conveying any form of emotion.
All Hallow's night snack is one of those quickies that people ended up liking a lot more than I anticipated. I liked it okay, but some said that this was the best I'd ever done, which surprised me. It goes to show that emotion and story is often more important than spending a lot of time on technique and detail.
Wrong Tunnel is an image I started out really liking. This was done in a faster and looser style and was great fun to do. It fell flat when it came to viewer appreciation though, most were rather meh about this one. I think it is probably a bit too hard to read with not enough contrasts to show the action. Also in retrospect the anatomy of the characters is really quite iffy. I don't remember why I never went back and fixed that, probably because I merged all layers and it felt like too much work to repaint it all around a vastly modified anatomy.
Skew World is one of my personal favorite pieces, something which is certainly not shared by all. There are viewers who literally feel physically sick watching this. Interestingly a surprising number of viewers seem to recognize themselves in the text (not sure what that says about our society though). It remains a niche image for sure, but I still like this a lot.

There is something about dragons. Almost all my dragon images tend to get an unproportionaye bunch of favorites on DeviantArt. I get the feeling it's the dragon theme in general which is simply very popular. My
Study of a Dragon's birth follows an existing style of Dragon that I've been developing and I like the image just fine. But it has a solid black background and is not really intended as anything but a cute little study. I'm quite surprised to find that it's up there among the most popular images from my DA gallery.
Into it's Element was an attempt at making a sort of thematic continuation of one of my most popular images
Out of its element. I spent a lot of time on this, made 3D models of the dragon to get the perspective right, made studies of the soldiers and all sorts of serious technical fluff.
And it just failed dramatically. The image is a total mess, with stark contrasts that is nigh impossible to read, a wide format that is just making things unfocused and confusing. Bleh. Sometimes not even a dragon can save an image I guess.

Lastly, this cute little study was surprisingly fun in that I sent it as a mother's day card and on the small screen of her phone my mum actually thought it was a photo. She were surprised that I had managed to get one that bloomed at that time of year. I'd call that a suprising success.
I think that's enough from me.

Let's hear your own stories.
.
Griatch