I've seen it repeated a lot that Blackbeard was actually very good to his crew, and when he'd board a ship, he would only resort to violence when the crew of the ship he was boarding fought back. Claims are that he never killed anyone who surrendered, or captives. He'd dye his hair and beard black, and just dress menacingly, and armed to the teeth to make himself look more threatening.
So, was that really the case, and if so, did most other pirates operate like that?
The stuff about Blackbeard dying his hair, never heard that one before (dying it that is) and the dressing menacingly is a product of Charles Johnson's General History of Pyracy, it's in the part of the chapter that's outright fictional.
Pirates liked to convince targets to surrender rather than fight. Pirates often picked targets they thought would be more vulnerable (and merchant vessels often fit that bill). Quickly demonstrate that they can be out-manned, outgunned, and even out-sailed, and that often convinced a ship to surrender. Unless the crew had something at stake in the ship (maybe they were venturing a small cargo, or had a share in) or thought they had a chance to run or put up a fight, surrender was pretty common. Pirates don't want to fight unless they have to, since fighting cost time, powder, and possibly lives (and these guys are in on this to make some kind of profit, which you can't do dead). Typically, there is no benefit to killing off a crew that surrendered - while the whole mentality of "don't make a reputation where crews won't surrender to you because they think they'll die if they do" is kind of there, pirates being fellow sailors and likely had some sympathies there, and captured crews offered opportunities for recruitment of new men for pirate crews (including specialists) that could volunteer or forced into the pirate crew if necessary.
Was it something Blackbeard came up with? No, others did this before him. The only reason he gets noted for this is because Blackbeard is a popular pirate, and many publications and shows on pirates get framed through telling Blackbeard's story since he's a popular one. Blackbeard got some attention from the newspapers and a notable highlighting chapter with some fiction mixed into it in Charles Johnson's General History of Pyracy (the latter really got the attention to his case going).
Some pirates were mean to the crews they captured, especially some after 1720. Ned Low slaughtered an entire crew of Spaniards after they surrendered supposedly. Francis Spriggs' crew tortured captured men for sport, including something called the "sweat" where a mast would have candles lit all around it below decks, and a prisoner would be made to go around the mast while a circle of pirates outside poked the prisoner with whatever sharp implements they wished (all to the tune of some musicians).
As a general rule for pirates across history, they much prefer people breaking under fear than actually fighting back and using violence. If your boarding a merchant ship, you have better odds but remember: pirates, for all their toughness and scurvy (ar har), are by no means professional soldiers or marines. They, as a generalization, are opportunists whose best way to ensure future monetary gain is by making their targets buckle without a fight. The second a pirate becomes more obsessed about fighting for the sake of fighting and not solely living and making money is the second Blackbeard is killed on the Queen Anne's Revenge. Terror over actual battle would always be preferred.