Depending on the class, also different levels of rigor may be required. The purpose of this is to build facility with the new mathematics and to expand your understanding. That's useless, because it relates the new as yet ununderstood mathematics to some other even less understood mathematics, and just adds to the prevailing haze and confusion. The theorem isn't understood because the student just takes it on somebody's authority rather than making it his or her own by coming up with a proof or at least reading and digesting one. Often it's useful to simplify the proof by adding simplifying assumptions or looking at special cases, and then assigning it to the students to fill in the gaps.
Students often complain that there's too much emphasis on proofs and too little on problem solving.
If you encounter that situation in my class then that's because I firmly believe that problem solving is more efficient and more powerful if it's based on understanding math rather than on following recipes.