Problematic learning situations (PLS) arise when students encounter learning difficulties and their teacher encounters difficulties assisting them. The current study looks at student and teacher difficulties revealed during PLS, in the course of instruction of basic geometrical concepts for average and below-average junior high school students, when teachers apply the strategy of cognitive conflict spontaneously and inefficiently. Re-analyzing three PLS detected while observing three student teachers (Gal in "Educational Studies in Mathematics," 78 (2), 183-203, 2011), I found that the teachers intuitively attempted to create a cognitive conflict but were mostly unaware of the inefficiency of this approach when students were not cognitively prepared. The findings point to the importance of enhancing teachers' awareness of how their students think, helping them interpret their students' understanding and encouraging them to seek the origins of student difficulties, so that teachers may be better prepared to reach a rational decision about an appropriate way to handle PLS. It is recommended to include these issues in teacher preparation and development programs.