Developer vs Tester

(Spoiler alert: developer wins)

My last developent was quite big and is now in our system testing department. So last week i got every 20 minutes a call from the tester, that something did not work as expected. For about 90% of the time i looked at the testing setup or the logs and told him, that the data is wrong or he used the tool wrong. After a couple of days i got mad because of his frequent interruptions. So I decided to make a list. Every time he came to me with an "error" i checked it and made a line for "User Error" or "Programming Error". He did not liked that much, because the User Error collum startet to grow fast:

User Errors: ||||| |||
Programming Errors: |||

Now he checks his testing data and the logs 3 times before he calls me and he hardly finds any "errors" anymore.