When a series of any kind starts to suck, it can be sudden (bad new writers/plotlines, slashed budget, etc.). The things that poison it just came out of nowhere.
However, sometimes there are signs that things are about to go bad. Signs you only see in retrospect.
I was watching the first two seasons of Nip/Tuck. I wanted to see if they were tainted by the disaster that show became. It turns out they hold up well. However, almost everything that made the show stupid and boring later is on full display in Season 2. An abundance of sex scenes and man ass which would get boring. The love triangle between Sean, Christian, and Julia. Wacky patients. Sean wanting a family structure at any cost. The carver’s identity being telegraphed from mile away. Matt being kind of a douche.
If I sound vague, it’s because detail isn’t really needed. The point is that everything that made Nip/Tuck suck in later seasons was right in front of me in the good times. It was just toned down enough to be tolerable (or even good). Is there any series like that for you guys?