No. "Threshold" is the worst episode ever. I give "Monsters" a 6, by the way.
These are the Star Trek episodes I
rate at the bottom. All the ones I give below a 5. I don't give ratings below a 5 easily.
TOS
And the Children Shall Lead – 3
Plato’s Stepchildren – 4
TNG
Code of Honor – 3
Justice – 2
Hide and Q – 4
Too Short a Season – 3
Home Soil – 4
Shades of Grey – 4
Tin Man – 4
The Most Toys – 4
Sub Rosa – 3
DS9
Let He Who Is Without Sin – 1
The Emperor’s New Cloak – 4
VOY
Threshold – 1
Thirty Days – 4
Latent Image – 4
The Disease – 2
ENT
A Night in Sickbay - 3
Precious Cargo - 4
"Spock's Brain" and "The Way to Eden" aren't on there because I enjoy watching them. They're in the "so bad, it's good" category. So, because I was entertained by them, but still recognize they're bad episodes, I split the difference and give them a 5.
You won't find "These Are the Voyages" on my list either because even though I can understand why ENT Fans would be upset with the series finale, I'm not an ENT Fan, so having Riker & Troi on there didn't bother me.