So what are the best openings
The best openings have a number of positive things such as getting your pieces out and developed early and not giving to many unfair advantages to your enemy.
All openings fall into three basic categories, Good, not popular and bad. So if we forget the bad, that leaves us with the not popular these are openings people like because they specialise in them and so while the opening might have more weaknesses than 'normal' good openings there is room for specialists to find advantages.
Generally White has the first move to break the balanced opening so should win more games. All good openings have some weaknesses but generally those weaknesses are not enough to give that opening to many disadvantages over multiple games.
So... the question again, whats the BEST openings ?
For White it must be the Scotch Game, why? because not everyone is playing it but it is solid and very very reliable and more importantly totally logical...
1. e4 is the most popular opening, so playing this gives no hint of anything unusual yet to Black.
2. it is proven solid and reliable and proven over time without huge new investments in theory etc.
3. e5 is a very popular reply to 1. e4 so that is the percentage chance you have. You cannot know if people are going to play 1...,Nf6 or 1...,c5 but if they play 1...,e5 then logically they are playing to your strong opening of the Scotch Game.
(Thats why this opening the Scotch Game is the best for beginners or advanced players alike since logically it has the highest percentage chance of getting into your game).
4. Your next move of 2. Nf3 attacks Black's e5 pawn so Black logically tries to 'defend' it with 2...,Nc6 (it is not logical for Black to mirror your moves with 2...,Nf6 thereby attacking YOU E pawn as you attack his E pawn).
5. So your 2. Nf3 allows you to play 3. d4, despite Black having played 2..., Nc6 so now you have your solid reliable Scotch game; an opening for the rest of your chess career to specialise it instead of some unusual or unsound novelty opening that will not serve you repeatedly against high level opponents.
So if the one BEST White opening is the Scotch game, what is Blacks' best opening? Remember we want only one opening to learn so we do not get donfused we want to learn our own game positions so that is why we need one 'best' Black reply to ANYTHING White throws at us.
So Black's best reply is the Caro-Kann, it is solid and reliable and proven and can meet anything White throws at it and serve. It is not totally popular but it works against anything White can hit it with. Sure it is not 'perfect' but it is more perfect than any other Black opening in comparison. This means the Caro-Kann has less flaws within one single opening for any different White opening to exploit.
So beginners have the Scotch game to learn and attack with as White and as Black a solid reliable defensive system that has pobbilities to attack White within the game.
Thus it is simply human nature to defy common-sense and try for any novelty advantage with different openings that might give them a higher percentage chance of winning.
So while variety is good to allow people to have fun, learn and experiment and reduce boredom; this opens a 'niche' marketplace for these two best openings for any players especially beginners.
Stop chopping and changing your openings just play solid proven stuff; PLAY the Scotch Game and the Caro-Kann, they can only help you win more games long term than any other two openings...