It's a joke about doing pointless things because he's at home. Nobody actually alphabetizes their socks, but he's saying he gets distracted and starts doing things around the house when he should be working.

To alphabetize your socks, you first have to name them.

Which is one of the hard problems. That's why it takes so long.

You always have a few pairs who disagree what their name should be.

You have pairs ! Consider yourself lucky.

GP gets distracted at home, to the extent of categorising their socks