The first characteristic is that people usually jump to the conclusion that the bass are stunted....which is rarely actually the case. Generally these lakes simply have healthy populations....lakes with super healthy populations always have tons of small fish this size because recruitment is often very high (ie excellent breeding success) and these abundant smaller fish are just the easiest ones to catch.
The second is that big fish on these types of lakes, rarely utilize the same areas that the smaller fish do....so if you are always catching small ones, keep trying new and different places using a wider variety of baits that can target larger fish...like jigs, big worms, or swimbaits. Fish deeper...or in heavier cover situations.
The third is related to the second....and that is that in these lakes, often, big fish do a lot of suspending over deeper water much of the year, these fish will always be very difficult to pinpoint and catch.
The rare lakes where populations are stunted will have very little cover and a poor panfish population and minimal baitfish. Often it can be obvious in a short time just looking around.
JME