When I say, be a sponge, I'm not recommending a sudden degeneration into a cluster of one-celled animals (though it would probably be quite cosy, apart from the having-fish-eating-you thing).
No, I'm recommending the soaking up of information.
When I was young, long long ago, in a house with few books and only one TV station, if you wanted to know anything then you had to be a sponge. Any piece of information had to be seized as it drifted past and then filed for future reference. The scraps could come from anywhere - TV dramas, novels bought for a few pennies from jumble sales (jumble sales were where people sent their old clothes and bits of tat to a public hall on a particular day be sold for charity), the conversation of adults - and checked against knowledge already held in the hope of making some sort of a connection.
I'm not naturally all that interested in Military History, for instance, but between CS Forester's Hornblower and Ronald Welch's Carey family I'm rather less ignorant than I might be.
But rather sadly there are other things people can soak up apart from knowledge, and one of them is money. If you sponge on someone then it's basically money, or the advantages of having money, you're after, and without any intention of anything in return.
I suppose it goes to show what a remarkable thing knowledge is: you can steal it from all over the place without anyone else losing it.
There's probably some great and important philosophical principle to be teased out of that, if only I knew what it was.
Venus Flower Basket sponge.
Thing To Be Not Do Today: sponge. This word has been unchanged in English for over a thousand years. The Greek form was spongia.