Collision Course vs. Crash Course

The question for this discussion would be why is collison course and crash course mean different things. Well this is a weird one. For this I must go deep inside my head of knowledge. Crash course meaning a first time at doing something. If someone gives you a crash course at lets say eating a bowl of icecream they might stick your head in the bowl and force it there until you eat the whole bowl. But ofcourse this would be very cold to your face and you would probably get a very severe cold freeze. Collision course, meaning two or more object on a trajectory of the same line at each other. Now what if someone gave you a crash course on a collision course. For example riding a bike into a wall. I think you would have a problem because for one you wouldnt be able to ride and then you would have many problems with the whole hall thing being in the way. Now kids that the lesson on Crash Course vs. Collision Course. Atleast both of them start with 'C'.