Quinn had taken his mother’s flask many times before, but he got careless this time, and his mother discovered it in his pocket. What caused Quinn’s carelessness?

I think that Quinn had taken the flask so many times that he became careless and was caught with it. I think he also has a lot on his mind.

According to common understanding, Quinn's sloppiness can be attributed to a variety of factors, including:

Overconfidence: Quinn may have thought he could steal the bottle without getting caught because he had successfully stolen in the past.

Distracted: Quinn may have been busy doing other things and forgot to put the flask away.

Urgency: Quinn may have urgently needed a flask and may not have had time to hide it properly.

Snub: Quinn may have forgotten the flask was in his pocket and didn't check it before leaving the house.

Ultimately, it is impossible to determine the exact cause of Quinn's negligence in this particular case without further information.