Good Intentions

Have you ever been faced with the idea that maybe some of your best intentions turned out to be your greatest failures??  It's a nasty notion, to be sure.  You begin whatever it is ....you're smiling.....you've got the world in your pocket....  there is only sunshine.  You are under the assumption that (whatever it is) is getting the best you have to offer.  And then.... you happen to glance up from your busyness for a second and to your utter dismay, it has all gone awry.  Have you ever had that happen to you??!?!  How can good intentions result in failure??  And how can it be prevented??  Is the answer more concentrated focus on the task at hand?  Actually, I don't have the answers....I'm going to have to mull it over some more.......