Tom Stoppard said this quote

There are no commitments, only bargains. And they have to be made again every day. You think making a commitment is it. Finish. You think it sets like a concrete platform and it'll take any strain you want to put on it. You're committed. You don't have to prove anything. In fact you can afford a little neglect, indulge in a little bit of sarcasm here and there, isolate yourself when you want to. Underneath it's concrete for life. I'm a cow in some ways, but you're an idiot.