I know you hear all the time from that you should pedal a high cadence. Generally it's a no-brainer, but there are some cases, especially with clydes and/or people just learning or recently getting back into cycling, where high cadence is a self-defeating bad habit.
I hate to see someone pedaling their ass off with a high (60rpm+) cadence in a gear so low that they really aren't getting anywhere...and usually get their HR up into the red zone in the process, even on the flats - usually evidenced by short spurts of pedaling with lots of coasting in between.
Don't get me wrong, spinning a high cadence is a good thing...if you can do it in a reasonable gear and pretty much continuously. Constantly coasting because either your muscles or your cardio can't handle it means you're pedaling too fast. Increase the gear, slow the cadence, work on your pedal stroke, keep your heart rate at about 80% of max and only coast when it's fun...not as a break for you heart/legs. Keep them legs moving...soft pedal if necessary. You have to learn to recover while pedaling and you need good, long, steady distance (LSD) base miles to build up your base fitness and form before you go trying to do Lance-rate cadence and/or racer-type interval training. You can work on increasing your cadence and doing intervals (aka rolling roads to many) once you have a good foundation of fitness, form and miles to build on.
Of course this only applies to those of you who have goals on the bike that include more than just having fun. If riding slow and coasting most of the time is what makes you happy, then by all means, enjoy!