As the first job, there is a lot of emotional attachment (totally normal) but it gets in the way of making rational decisions. In particular, most people will harbor somewhat unrealistic career goals while being at the lowest rung of the corporate ladder and thus being the most disposable.
Additionally, interviewing at and getting other jobs makes it so that the process isn’t unknown or scary.
I just think that you should always remember that, at the end of the day, it's still a job. If you remember that fact, it hurts less being laid off, and it's easier to quit a job if/when it becomes toxic.