Tires make or break the car

I have a fun car that I built 20 years ago.
It has a spare tyre that is 20 years old.
I had a puncture earlier this year, so I fitted the spare, the handling was shot, managed a 360 spin on a gentle corner without hitting anything.
Realising that the spare was round and black but otherwise useless I drove home very gently and did not drive this car again untill I had repaired the punctured tyre (simple nail through center of tread) and replaced the spare.
In short I agree that old tires are useless.
I always try to replace tires as an axle set.