It's very tuff to answer fronkly as i have found nearly 2500 issues on my project as this is a long run product and clients are keep on coming , but for interview point of view i can give one example.
We have a reports module, in this client has raised an issue that date range is not being calculated properly for periods.
Ex: Today is 08 Dec 2008. monday
Data range (drop down) : This week : <First day of this week> to <Current day>
last week: As above
So the actual dates are : This week : <8-Dec-08> to <08-Dec-08>
Last week: <1-Dec-08> to <07-Dec-08>
For us report shown as expected, but for client it's shown as below
This week : <8-Dec-08> to <07-Dec-08>
Wonedered as how he got the issue, we both dev and testing team verified and spend so much time but never found, one ween end i gone to office and tried with a fresh mood.. found the reason with in 10 mins..at last reason found by me. :)
Reason: Issue occured if and only if ran the report on sundays, we have never worked on sundays, so this is the reason.
Finally i can said this is one of the best bug found in my life.
