Putting too much paste on a socket generally won't hurt thermal performance, because the act of tightening down the cooler squeezes out the excess. Too little paste is bad, but anything above the minimum threshold will have the same effect once the cooler is tightened down.

What happens if you add too much thermal paste?

Don't put on too much thermal paste

When you apply too much thermal paste, it can act like an insulator. At best case, this may make the paste ineffective, and at worst case, you may damage components via overheating. Make sure that you apply a thin layer of paste to your component.

Can too much thermal paste ruin a CPU?

Because the cooler plate and the CPU are so close, too much paste can expand out beyond the chip and the plate, filling into the space of the CPU socket itself and transferring undesirable heat to the CPU's electrical contacts or the surrounding PCB. That's bad.