So I'm currently using pet tape on my print bed heated to 60c.
That was fine, I was having a few adhesion issues so started using a glue stick and calibrating really tight.
And that was all fine, still occasionally having adhesion issues.

And then I remembered that when i bought simplify3d I had intended to slow the first layer speed right down. It'set to 50% by default and I had never actually trie changing it.
So i did that, dropped it right down to 10% of printspeed and it works a treat. Everything sticks like a super limpet on steroids.
I was then getting a few removal issues (ie: swearing at the machine a lot, and getting some odd looks from the dog). And was going to either wipe the glue off or calibrate slightly less tightly.

Didn't get round to it and last night ran a big print with models covering the majority of the build plate.

And it's taken me the whole bloody day to finally get the last one off !

I ended up by heating the bed up, wiggling a scraper a few mm under the model while it's warm. Waiting for the bed to cool, getting the scraper further under and heaving with great effort.
I now plan to clean all the glue off the plate.

Just glad I didn't print a single large model that covered the whole plate. Not sure I'd have ever got it off.

Conclusions:
1) Yes you can have too much adhesion.
2) the best thing you can do to help model adhesion is to slow your first layer to 10% of the print speed.
3) you don't need to use: glue, heat, slow layer, and really tight calibration all together.

That was a real sod of a job.

This game is a constant learning curve. I'm going to wipe the glue off and try it with just bare pet tape and slow first layer.

Oh yeah and I'll have to replace the tape - that got torn as well :-) (and that's not easy)

So, yep, you can get carried away with wanting more and more adhesion.
Still I suppose it's a better situation to be in than still not being able to get things to stick :-)