Wormtail did a lot to bring back the dark lord. But his efforts were mostly ignored. The others were looking down at him, treating him like he was worthless. Now he was in Malfoy manor, together with the Malfoys and Bellatrix. He couldn't stand them. He had to do little works, almost like a house elf. Despite how he was treated he tried his best. He still wanted to be respected and so he just tried harder.