Varying clutch pedal feel/pressure '91 300zxTT

[w8lifter21]

Ever since I have had the car, I have felt a varying clutch pressure feel.(About 3 years/5000 miles) Never been a problem, then one day it was very hard to get the car into 1st. Finally was able after about 20 clutch presses. I was able to get the car home, and a few days later I bled the clutch up under the hood. Now I am at least able to drive/move the car.

Underlying question is, what would cause the clutch to have a varying feel while pushing it in?

Example out of 10 shifts:
8 of them would be the same
1 the pedal would be harder than "normal"
1 the pedal would be easier than "normal"

Rough example, but the only way I can think of at the moment :-)