Human attempts:
1st attempt: battery horse staple correct
Result: Your user name or password or captcha is incorrect.
2nd attempt: horse battery correct staple
Result: Your user name or password or captcha is incorrect.
(Brb 5 mins to look it up)
3rd attempt (impatiently): battery horse staple corect
Result: Your user name or password or captcha is incorrect.
4th attempt (getting angry now): corrcet horse battery staple
Result: Your user name or password or captcha is incorrect.
(Brb 10 mins to calm down, then each key slowly and carefully): correct horse battery staple
Result: Success!
(Depending on readability of captcha.)
Computer attempts (after buying a list of account details and a lookup table of hashes on the internet):
1st attempt: h17sod9wjjasjdhasdd97wdhdjndmdb (and AI on captcha)
Result: Success!