A/C recharge problem -- non-Prius -- any help?

My old Camry's A/C works, but nowhere as cold as it should be. Just tried recharging it myself.

I once attempted this on a Tercel, back around the mid-1980s. In those days, the HIGH and LOW sides were not marked as they are in more recent models.

Well, it was a hot Sunday afternoon some 35 years ago and a few of us 20-somethings had been drinking a few beers and -- yep -- you guessed it, I hooked up the recharge can to the high side. Luckily, it blew the hose and not the can, so no serious injuries.

So, I was not anxious to do this again -- but:

1) Bought gauge -- hooked it up to LOW side -- reading ZERO.

2) Attached can of the correct refrigerant (134a or something like that).

3) Punctured can of refrigerant -- gauge immediately reads -- in the DANGER WILL ROBINSON zone -- at the very top of the gauge.

Pulled off can of refrigerant from car. I later installed gauge and checked pressure again, it still reads ZERO.

I had the car a/c and fan at MAX and had had it at MAX for at least 15 minutes before attempting this. Temperature at the time of this was 81 degrees F.

So, what did I do wrong..... BTW...coolant hissed out of the recharge can for a good long time after I pulled it off the car until it was totally empty and I received slight frostbite of an index finger.

Any answers -- criticisms?

Oh, just realized that most of you will have no idea what my red highlighted phrase means -- it comes from an old TV show....Lost in Space: