It gets tiring fast and services don't deal with this usecase that well other than 'forget password'. That guy was the initial asshole to signup using an email address that wasn't theirs.
so my email address is very simple. I have someone from almost every English speaking country who regularly uses my email address for all things mundane, profane, inane and urbane.
I used to respond to each and every one if possible, politely asking them to remove me from the list, stop putting my email down on whatever forms they were filling out or to tell the person they got the email address from to use their own or be more careful when filling it out. It's been going on so long and gotten so bad that I just can't anymore.
examples of things I have received mistakenly in my email that were clearly the result of someone entering them in a form or writing the down to be used by someone else.
Job interview confirmations for fields I am not and have never been involved with
letters from grandma
plane ticket, concert ticket, train ticket, parking ticket and other types of ticket confirmation and notifications.
boating licenses
requests to accept changes to architectural plans for a house
lease and housing agreements
notices to appear in court
electronic receipts of every sort
prescription drug receipts
confidential internal company information
and more.