The vast majority of players on these forums should aspire to become TAG-fish. Furthermore, most very good players should play like TAG-fish in the absence of a read about their opponent.
The chief characteristic of a TAG-fish is the inability or unwillingness to adapt to playing against other good players. That said, most inexperienced players spend far too much time leaking against bad players who they mistakenly think are exploiting them.
It is generally better to be exploited by a good player than mistakenly adjust to a bad one.
P.S. Also, most of the characteristics players who don't know what they are talking about assign to so-called "TAG-fish" are actually characteristics of tight-passives. C-betting flops does not make you a TAG or a TAG-fish. TAG-fish are usually extremely, exploitably aggressive.
I think being a tag-fish boils down to imitating good players. You don't understand why you do what you do, but you do it b/c ppl on 2+2 would say to do it or you saw a good player do it in a training video (I was a tag-fish for way too long, and I think everyone goes through this stage in their development).
I think the majority of posters who just come to this forum to post hands take that approach to the game. They want to be told the right answer so they can use it next time. But it's not about memorizing a bunch of right answers, it's about learning the reasons for why the answer is right. It's like the cat and mouse game math professors play when they say "the numbers will be different on the exam" so you can't just memorize correct answers. Still, if the problem is in the exact same format you can rely on memory to a degree instead of truly figuring it out on your own. In poker you're always on your own and the problem is always brand new