Passwords can be brute-forced i.e. another computer or computers to try all possible combinations of numbers letters and punctuation including dictionary words and other likelies but also even seemingly random passwords can be cracked in minutes according to this calculator.
Apparently my desktop PC user password could be done in 2minutes 30s – eek 😮
My strongest one would last 24 hours 25mins though which is a little more reassuring..
However it all depends on what computing power they are throwing at the job and the site doesn’t tell us that
BTW there’s lots of little tools like this banging around the internet, just in case you weren’t aware