Humans do make mistakes, but ...

I went to the Toronto airport. After waiting for a long queue, The person asked my name and started to set up my ticket. After a few seconds, she replied:

- Sorry sir we can not find your name on the list of the passengers.
- I have the print of the e-tickets.

She got the documents and gave them to another person. After a few minutes she came back and said:

- Sorry, there is something wrong with your ticket, please contact the organization whom you bought the tickets from!

Well, I should say the place was close, and right after I showed the staff my documents, they told me:

- What are you thinking? Today is 26 of July and your ticket is for 26 of June ...

Yes, I bought a new ticket and went back home. I am still wondering that was that my mistake or the computer's mistake ? ... Well, I am a computer scientist. It is better to blame myself instead of my research field ;)