Low ratings have two general categories, idiots and disgruntled. Idiots are the people who have pebkac problems and just fail at understanding the product or its usage. These people leave one star reviews on hammers saying "doesn't pound nails only smashes fingers". These reviews I totally ignore and actually make me believe the product is decent when used correctly.
Disgruntled reviews contain details on why the product is bad. They usually convey a sense that the reviewer understands and is competent in using the product it's that the product actually is failing in some way beyond the user's control. These make me believe the product itself is bad.
The thing is, most of the time one star reviews tend to be of the idiot category.