Since I contributed to derailing this thread a little, I'd like to put something positive now

My basic understanding of a TAG, is someone who builds his game around maximizing his FE vs a LAG who maximizes his SD value.

I'll elaborate. TAG, LAG or a purplepuppyfish for me is not the preflop numbers or some mythical stereotype of a player. You can be 40/30 or 18/16 and still a fish (what this forum refers to as tagfish and lagtards)

There is a certain way of playing which is called ABC poker. Its profitable against fish. Reliable. But not always the best against better players. LAGs TAGs and tagfish/lagtards all employ it to a certain degree.

Now the difference is, a tagfish plays ABC poker.

A good TAG plays ABC poker AND abuses his tight image rarely making big moves against opponents. This is what makes him a better player and a feared opponent. He has FE and he knows how to use it. His big showdowns against regulars are usually close calls and more or less coolers to one side or another.

A good LAG plays ABC poker AND constantly abuses small size pots propelling a crazy aggrodonk image both pre and post flop. Not necessarily a very profitable thing on its own, but certainly increases his chances to get paid when he has a hand. His big showdowns against regulars are usually monstrous.

A lagtard plays ABC poker and absuses small and big pots without any difference. He does get paid and steals a lot at the start, but usually goes broke before he catches a series of good hands.

Now a good player does not just play tag or lag or whatever. He switches gears constantly.

There's no real 'optimal stats'. The stats which will make you the most money depend on your ability to play postflop and your edge over your opponents.

If cts dropped down to 50nl I gaurantee that 21/17 would not be optimal for him, probably something closer to 40/30. If a complete beginner started out playing 5nl then 21/17 wouldn't be optimal for them either, probably something much tighter.

As you get better you can play more hands profitably from more positions, provided your opposition stay at the same level (i.e. you don't move up). When you're starting out, having strict (and tight) starting hand requirements is a good thing. It keeps you from spewing all your money, from getting in very difficult situations, and allows you to gradually improve.

Then you have to take into account table dynamics, your image, and game flow to determine what an optimal preflop style would be at that time. Saying that 21/17 is optimal is meaningless, it may be optimal for you given certain table conditions and at certain stakes but as you improve having strict starting hand requirements will hold back both your winrate and your ability to improve.

I agree with RedJoker about optimal stats. There are no optimal stats in a vacuum. Since in all hands we discuss we want to know something about our opponent, it is totally obvious that our decisions change when our opponents change. A different set of decisions will usually lead to a different set of stats.

As a further example:

I think more of those stats discussions are pretty useless. Everybody seems to think W$WSF > 45 or 50 is so sexy. This is very much dependent on the opposition. On I-poker and Party I have seen people playing nitty/weak-tight poker. These guys have a good idea about preflop stats, but are not postflop geniuses by any means and play too much fit or fold. It's easy to W$WSF high in those games.

On my usual site I get plenty of action playing 17/14/3 and I am playing some draws pretty passive because there fold equity is usually lacking. This results in a lower W$WSF (~37 or so), but in a higher winrate.