Being stuck in an old, grimy house like Grimmauld Place made Sirius irritable and restless, especially when other members of the Order were out there doing their part for the cause.

Source: https://www.cbr.com/harry-potter-sirius-black-quotes/

Not only had isolating Harry been a bad idea, but Dumbledore forcing Sirius Black to stay at Grimmauld Place had only ensured that the man would take off at the first chance.

Source: https://screenrant.com/harry-potter-order-phoenix-dumbledore-book-confession-cut/