This problem is a small one and it can only occur with manual cars, but I have been curious to find out more about it for a while now. Sometimes, when the car is attempting to pull away from a standstill (at traffic lights, for example) the driver will put the clutch down and try to put it in to first gear. They either have to exert more force than most would feel comfortable in doing to force it in to first gear or try again and it will usually go in the second time. A few cars that I have driven or been a passenger in in the past have had this problem.
It also happened with the reverse gear (as well as first) on my old car, but I would need to lift the clutch just a little from the pedal down position in order to move the gear stick fully in to the reverse gear. To get it in to first I just had to use a bit more force than the manufacturer intended.
I wonder if the problem occurs primarily with first gear because that is the one that is used the most. I have only noticed this issue on older cars (10+ years).
What is the gearbox doing mechanically when the car won't go in to first with the clutch pedal down?
Is it going to lead to a damaged gearbox or have any other bad knock-on effects?