A couple of other thoughts to add to your brew witterings ...
Apparently squeezing the teabag adds more tannin to your tea cup, adding a bitter after taste
And I also remember being told that the triangle bags were a result of a malfunction in the 'normal' teabag producttion line, it was not an intentional plan. The result gave off more tea taste than anything they had so far achieved in the lab, including the round ones.
OTC