OP I will share my 4-year-anniversary post with you because I think it will help you:
https://forumserver.twoplustwo.com/3...32/?highlight=
Keep playing and having fun - seriously, "having fun" is the most important thing. Don't let poker become a job or a college class or something like that. It's a GAME. You PLAY A GAME to have FUN.
As a reponse to your specific point, don't worry about it. As you gain experience you'll learn to spot the people who do things like play very loose preflop but very tight postflop, or crazy people who bet and raise with anything, or TAGs (tight-aggressives) who wait for a big hand and when they hit bet like they're trying to shovel money into the pot, calling stations who will not fold no matter what etc.
And it will annoy you in the beginning when you have a read on someone and then they play a hand totally contrary to what you expected, but eventually you'll learn to tell if it was bad luck or a bad decision.
Don't get discouraged - have fun!