From where do we know that one must have respect and awe for a Shul?
From the verse in this week's Parashah: "He should not enter all times into the Holy" (Vayikra 16:2). One may enter only when he is full of awe of Hashem within his soul.
This is why Nadav and Avihu were punished! It is true that they entered the Mishkan and we are discussing a Shul, but a Shul is called "Mikdash Me'at" – a minituare Temple. In our times, to our great distress, we do not have the Temple, so the Shul is Hashem's Temple.
It is permissible to jump, laugh and fool around (a little), but not in Shul. This is a holy place.