Even seen a middy plant?

Ive seen quite a few grows in my young days which consisted of lots of high grade no name strains, ya know just some good smokes nothing like green crack or blue dream though. One thing I have NEVER seen is a mid grade plant. I have seen plenty of mid grades to make me wonder wtf, it didnt come off the plant like this. So my question is why do some mid grades look so ugly? Ive seen good mid grades with minimal stems and maybe a seed or 2 every eighth or so with the nice green. What I dont understand is how some mid grades are nice looking while the others are ugly and hard to break down but still smoke the same as the the fluffy green stuff.
For those who dont want to read that.
-What does a mid grade plant look like?smell like?size? grow time?
-Howcome the mid grades can look like shwag but still be good smoke?

The quality of smoke is generally determined by genetics however when it's picked and how it's cared for are factors as well but no matter how well it's cared for and even if it's picked at exactly the right time the genetics will determine the THC content. I'm not sure a mid-grade plant looks any different then any other plant. A clone will be a carbon copy dna match of the mother plant, a seed will carry the dna of both mother and father so there is an unknown variable but in general the seed will produce similar buds to what it came out of but it could be better or it could be worse. I've seen killer green bud grown from seed INDOORS that produced no high! I smoked half an 8th to my head and kept wondering when it would kick in.

Thanks for the informational reply -_-
The only time i ever smoked that amount and didnt get high was when we had a drought and I bought 40grams of some of the shwagiest buds ive smoked ever for 60 bucks taking into consideration my dealer is like my brother and i used to flip his little weight around, talk about good ole days on the block haha. until he met my other connect from michigan i cant really ever get to :(,and started getting high grades and man when good high grade comes around here in va it goes like crazy

The mids plants that i've grown look pretty standard up until flowering starts. Colorful pistils and hairs start to emerge on the ' flowers ' or buds. In my encounters if the plant gets shaked or disturbed it emits a nice skunky smell. Otherwise it looks just like any other green pot plant you've ever seen.