It has been hinted at. It has been stated outright. It has been emphasized emphatically.
If you have been doing everything correctly for your plants and they still look pathetic --- you are most likely not giving them enough light.
The secret to getting them to look their best, is LIGHT. Lots of light. If you can't give them high levels of fluorescent light, give them lower levels for longer periods of time (24 hours per day works well for me). I have no experience with using natural light for this group, so I will not attempt to advise you concerning natural lighting.
It might help if you think of it like this:
If you had a car and you expected it to provide you with reliable transportation, you would go to the greatest lengths to ensure that its maintenance were kept up. All essential fluids were kept optimum, you wouldn't crash it repeatedly into whatever obstacles you could find. You would be very careful with it and provide it with all the cleaning and maintenance that would keep it working well for you. But you wouldn't expect to travel indefinitely with only one quart of fuel. I know it is not an analogy that fits well, but just like automobiles need fuel, plants need light, and, of course, everything else too. And, like automobiles, all things necessary must be kept in balance.