Technical errors

A few days after my return from single malt country I went to the airline webpage to see if it was possible to get the cost for the car rental reimbursed. According to EU regulations, air passangers have certain rights to compensation if flights are delayed or cancelled. For instance if your actual arrival time is more than two hours after your schedueled arrival time. But of course certain conditions apply; no compensation is given if the reasons for the delay or cancellation is beyond the airlines control. Well, I am still good I thought, it must be an airlines responsibility to keep planes in shape for flying. But I was mistaken, I wasn't entitled to any compensation since the reason for delay was "unexpected technical error". What the f... does that mean? Do airplanes ever suffer from expected technical errors? What's the point with these regulations if they never apply? Do anyone ever get any compensation? Or are they just there to keep passangers smiling and happy and easy to deal with? Come to think of it, that is a very good reason.