I would say that in all beers, controlling hte temperature of the fermentation has the largest effect on the final product of nearly any step we take. It is very important.
This is doubly true with lagers. Not be mean, but I highly doubt you got a good clean lager profile fermenting a lager strain at room temperature. You have made what is generally called a steam beer. Lager strain through a ton of flavor when fermented at warmer temepratures and these flavors are not in line with the typical lager taste profile (maerzens, pils, helles etc.).
Temperature control will greatly improve the quality of your beer. This is true in the science of brewing, and also from personal experience.