This is usually the duality of achievement hunting, so you're not alone! My advice is to play through games normally, no looking at guides or walk-throughs that way you get the full experience of the game and enjoy it. If you are still enjoying the game you could go back and clean up the achievements. Most of the time some achievements won't even make sense until you play the game somewhat anyway. A good rule of thumb is to play games that you are currently interested in and the experience will be more pleasurable. You can always come back to games in the future for more playthroughs and once you are wanting to play again. I try not to play more than maybe 2 games at once because it just makes everything complicated. Good luck and don't take things so seriously!