yeah the first thing to realize about cycles is by default it only renders 10 samples which is only good for testing. I usually set my render for testing at least at 100 samples and the final render to 1000. Sometimes it doesn’t require that many samples though. Also the next MAJOR point is that you will not get a very desirable render without stuff around your objects to bounce the light off of. By default the environment emits a dull grey light from every angle and you have one dim bulb to light the scene. Pretty much a terrible default scene if you ask me because you could never render anything with it.
Took me a long time to figure out why my renders looked so washed out. Well it was because I was getting the same amount of light from every angle. You can fix this by using HDRI images as your background and/or adding things like a plane under your object and/or walls. You have to have stuff to block the environment light and to bounce the light onto your object. I think this is the essence of an unbiased renderer, though I may be wrong about that.
You can get a more controlled scene by turning your world color down to black too. At least that helped me to understand the effect it had on my renders. I almost never do this now. I usually add HDRI images as the world environment texture, because it has inconsistent lighting which adds a large level of realism to any scene. I do however always turn off the the visability of the environment texture from the camera so it doesn’t render. Though that is just because I only use a couple different textures and they don’t look good for my purposes in the final render.
Yeah and like moony said, you’ll run into fireflies at some point. That clamp value usually fixes those, but there are other “better” methods to fixing those through nodes, but I haven’t quite been able to wrap my brain around that yet.