Camera Trajectory makes big curves for nothing ??

Hey ! This is a problem I have had for a long time. I always manage to get over it, but this time it bothers me a lot. The trajectory of my video camera makes curves for no reason which are often very exaggerated! When I want to do a simple tracking shot, the camera necessarily wants to make a curve in the ground, or in the air. Why ?

I just did a lot of testing, and I think it happens when I create one key over the other to make small breaks in my video.