The only parts of building that I really don't like, are:

1) Having to substantially re-engineer something that was badly designed or manufactured. (I don't mind engineering something from scratch, but I hate having to redesign stuff that the manufacturer screwed up, coz I already paid them to get it right).

2) Having to have an idle workbench because I'm waiting for parts to arrive that were supposed to be in the kit, but were not. A proper parts list in all kits would help reduce this issue from cropping up several times per kit.

Gordon