Teaching classmates who don't put much effort in
In my experience, undergraduate students are a lot like children. They will be as lazy as you allow them to be. They will resist learning. They will resist doing the work and putting in the time. It's human nature...and it is something we, as teachers, must get the students to change.

Were I in your shoes, I would make it clear how to do something (as any teacher should) but I would certainly NOT do the work for them. If they keep saying "I don't know" then you should tell them "It's OK. Not everybody gets it their first time. Perhaps you get it when you take this class for a second time." I usually see my students' eyes open a bit on this one as they see that you are being so compassionate and understanding while still being refused to be manipulated. They also get the clear understanding that they will fail if they don't do the work.

We need to help students. That includes helping them to not be so lazy.