I already explained it:
Laguna says-"I usually didnīt take this path" or something along these lines.
Would Laguna have lost his memory before this event he wouldnīt remember the path he used to take and would not realize he was doing something abnormal.This way he wouldnīt prevent the forces acting on him.
In fact,a person without memory didnīt have an identity and thus he thinks he IS the person possessing him.He donīt try to act like himself because he didnīt know this "himself".
That is what possession is about on FF8.
Full possession like the one of Edea only occur on the assymptotic limit in which ones memory is fully erased.

The very fact that Squall donīt like Laguna means nothing.
It would not prevent Squall to choose a different path.
Maybe he thinks that path is better.