It can go wrong so it will!
Flying your own or a very small group aircraft it is probably much less likely - because you have a muc better awareness of how much fuel you put in..
But - my last aircraft had a fully approved CAA flight manual - which had no fuel consumptions figures at all. The third fuel tank - the largest one - had no fuel gauge and all this on a C of A aircraft. No this same aircraft has a fuel consumption varying from 12 gallons per hour at full throttle to 6 at a lazy cruise. So you do not need to be very imaginative to see just how easy it is to get it wrong.
No one plans to run out of fuel - it happens when other things impact upon the fuel state.
Two weeks ago I was undertaking a professional float flying course, at the end of a gruelling 2 hours session we started back for the home base. (For those who have not done this fuel consumption varies between about 2 and 14 gallons per hour for this aircraft).
We encountered severe turbulence and the gauges were virtually unreadable, but bouncing off the stops. After a review of what we had been doing we (the instructor and I) thought it prudent to return to the lake over the calm air and check. We did that and then assessed the wind versus remaining distance. It was not a comfortable thought and so after another couple of minutes of trying to think of an alternative we set down on the lake and tried to get some fuel delivered - which lead to a pleasant afternoon waiting....
But it does require real discipline and that is much easier in this sort of environment. End result was the aircraft had at least 75 minutes of fuel at cruise consumption more in it than the gauges and the dipstick suggested - which meant what we had done was compleely unnecessary......