# I can be 2; I can be ∞

I can be 2

I can be ∞

The more I have the more I wont favor you

The less I have the less fun

I bring tense to my owner

People from any part of the world knows about me.

3100 to now I still work

I like to play board games. I have faces but no expressions.

A bit far-fetched, but still. You are

Elo rating in chess (or other games)

I can be 2
I can be ∞

Well, Elo rating system is technically unbounded, so the rating of a player can have any value and even be potentially infinite (although it's highly unlikely due to the possibility of draws, so even the so-called "God player" will have finite rating)

The more I have the more I wont favor you

Well, the greater is the opponent rating, the less are the chances to win/draw a game.

The less I have the less fun

On the other side, it's not interesting to play and analyse at very low level. Grandmaster games are usually more interesting to watch and analyse.

I bring tense to my owner

Of course, a high-rated player (a GM or so) will bother about playing results.

People from any part of the world knows about me.

The rating system is global and universal, in fact, everyone who plays online chess knows about rating system (even a bit).

3100 to now I still work

Despite official FIDE ratings are much lower than 3100 (the most top-rated GMs, including the current world champion Magnus Carlsen, have about 2900), but the top online ratings AFAIK had reached 3100ish values. Of course, Elo system still works and is a convenient way to rate chess players.

I think it is

the unknown from an equation.

Reasoning:

I can be 2 / I can be ∞

That is why it is unknown

The more I have the more I won't favor you

the more unknown the harder it is to solve

The less I have the less fun

the exact opposite of before and this is true

I bring tense to my owner

solving is quite stressful

People from any part of the world knows about me

mathematics are worlwide and that is a quite good joke the "knows about me"

3100 to now I still work

The more complex math started to appear around 3000 BC.