A coworker and I were discussing a gal who was let go during the probationary period. She was dumb enough to show her slacker side way too early in the relationship.
If you were dating a hot guy or gal, wouldn't you clean up your place before a visit? You wouldn't want to show what a slob you are until you'd reeled him in a bit. You wouldn't criticize his nosy mother, loudmouth brother or irresponsible friend too soon in the relationship.
The same with a new job.