Let's discuss about playing chess online and how this (can) affect your game.
Playing chess online
Because there are now a lot of chess sites, many people play chess online. It is much easier than going to a club or tournaments. A chess game it's a click away. But that click can affect you.
Just playing
Because people should just click a button to play a chess game, they stop training.
Training=doing puzzles, reading, taking lessons etc.
Why do many people stop training? Because it's more simple to click a button and play the next game than learning a new opening, strategies etc.
In a real game
Before a tournament or a match with your friend, you are training, because you know you are having a single chance to win. People are training harder, because on a tournament you are eliminated if you lose.
What to do?
Start playing less games a day.
Train more.
Try to play a game thinking at it, not at the next game.
Play just 1-3 bullet games a day because for many people bullet it's luck.