Bubbles are the norm for a big screen with a screen protector. You can be an expert in installing hundreds of these things, yet you may well get bubbles after the 500th screen protector you put on. Its not a guarantee.

Apple stores in the US I think was told to stop selling the screen protectors largely because when installation goes wrong, people ask for new ones.

When I worked in a spectacle shop before, we always gave free service for adjusting your frame, but we always tell the customer up front, that if it breaks for whatever reason during adjusting, its your own cost. Nitpick all you want, but unless you actually pay the guy money to install it perfect for you, don't complain if you are not satisfied with the installation.