The biggest mistake I can see is taking a very short run of results and making an assumption.

E.G. just recently I suffered my biggest daily loss in 5 years. I have to tell you it ruffled me something terrible! I couldn't believe the 6 nags in question didn't run a place, followed by 4 losers from 5,... beyond belief. (7 ran 4th)

but i stuck to the guns and recovered in 2 meetings, one with 5 straight placings.

You have to realise that you need 1000 results plus to make an accurate assumption.