When my son turned 1, he also turned Into a total butt hole. What happened to my perfectly behaving baby. He screams and crys real tears if he doesn't get what he wants. My husband and I are worried we ruined him by "spoiling" him.
You didn't ruin him, he's one. You just have to start laying down ground rules and boundaries. Teach him that no means no, no matter how much he cries. Don't given in because kids are smart and will keep pushing because they know you have a breaking point. Try a quick cool down time out.
I put Lincoln in the pack'n'play for about 1 min while he's acting out. He can't come out until he lowers his voice and stops throwing a fit. He's gotten so much better.
Even the most well behaved toddler has temper tantrums. There are a whole boat load of parenting books and websites out there dedicated to helping parents manage them. 1 year olds don't have any sort of emotional filters yet. If they're happy, you know it and if they're frustrated/upset, you know it. It's a long process before you can start getting bent out of shape about temper tantrums. If the kid is 4 and still acting like a 2 year old, then you've got issues. At 1? Part of the fun of parenting.