This, plus also if you use a tiny air bubble at the end of the syringe to push the last drop of Gear out, that bubble could cause heart/lung/brain injury if it gets into the blood stream, I've read. I don't remember the exact details, but just the idea of causing any kind of preventable heart/lung/brain damage, is stupid to me.
Haha, but seriously I have just never aspirated once over the years - the only thing I have stopped doing or modified is stopped injecting into my traps. That was quite a weird sensation. Tren Cough hits IMMEDIATELY when you get it into the blood stream, however nothing has ever caused any detrimental effects.