My problem is consistency from session to session, which breeds impatience and tempts me to buy a jig.
When starting out, I wanted to be much better at it than I was, so I learned some bad habits. I tried the magic marker trick a half a dozen times, but hated how it messed with the color of the swarf and gave up on it. Then I spent a good deal of time retraining myself, slowing down, paying more attention to the stones and the steel, and have gotten much better. Still, there are days when I sharpen my work knife and get ****** results, and other days when I sharpen it and get that spooky edge that makes your arm hair tremble in fear. Couldn't tell you what the difference is from day to day, but on the days that I'm "off," it's pretty damn annoying.
An example... after getting my CCK I spent quite some time trying to "open it up," and at the end of the session I had an edge just barely sharper than it was out of the box. Just couldn't get it right. But the next day after work, I was supposed to meet a friend at the bar for drinks and to loan him the cleaver. Since I'd beat it up at work that day and was already late, I gave the Bester 1200 a quick soak and then took the CCK to it. The burr popped up like nobody's business, I flipped it a few times, removed it, and then stropped a few times with chromium oxide for a bit of polish. 5-6 minutes tops I think? The edge sung when you thumbed it. It was stupidly sharp, off just a 1.2k.
I can't tell you why I did a better job when I was in a rush to meet someone for drinks than when I had all night. A skill this temperamental "doesn't compute."