I remember one time just after needle insertion, I dropped the syringe. Yikes! I didn't do that again
This is an interesting topic that has a serious side too.
I always took care to get all bubbles out of the injectable and also to make sure there was no air in the syringe. Turns out that care might have been misplaced.
If air is good as Paul said, I can see a case for leaving .1ml of air at the end of the syringe, and not to worry about
the bubbles. If you inject with the plunger end of the syringe higher so that the big bubble rises, you achieve the mission of getting all that maybe expensive injectable to where it oughta go, and not waste any by leaving up to about
.1ml in the syringe. What is left in the syringe will be air.
Let's hope the air we do inject is sterile