Don't throw it across the room!
If you enjoy blackwork but don't enjoy unpicking because you have done all of the outside and it doesn't meet where it should, don't get frustrated and unpick the lot!
Start where you know it is right and stitch some of the main rows of the "fill-in" pattern you will soon find where you have gone wrong.
BUT I hear you cry there is a dark mark where the stitches were!
You need an 'Artists Putty Rubber'. These can be purchased from any good art shops and last forever! Just rub over the dark marks and the rubber picks up the fluff and "voila" the mark has gone!
When you have finished your stitching, gently wash your work. I actually use "bubble bath"! (Well if it is gentle enough for our delicate bodies it should be OK for stitching in my opinion!).
This is a tip rather than cleaning advice especially if you use rayon threads :-)
At the same time you purchase an 'Artist Putty Rubber' purchase a piece of 'Natural Sponge' these come in quite tiny pieces. Dampen the sponge and then run rayon thread over the sponge this will stop the thread being springy. Treat like 'Metallic Thread', just use short lengths.