This doesn't make sense to me. Say I'm a market maker. How do I make the spread bigger than it would have been if I was absent? I suppose I can hit any order

This doesn't make sense to me. Say I'm a market maker. How do I make the spread bigger than it would have been if I was absent? I suppose I can hit any orders anyone else places inside my larger spread, but that just gives anyone the opportunity to pump money out of my accounts...