Disappointed students......

Its already third week teaching in school. I find teaching the students nowadays are much more different compared to few years back. Is it due to SPN21 which the students think that they do not need to work hard to get promoted to the next level? Last week I punish a boy due to he was not paying attention to my lesson and was laying his head down onto his desk, so i decided to call him and he ignore me so i pulled his ears. He shouted at me and throw his files and stationery on the floor. I called him to pick them all up but he was not satisfy and kick his desk and chair. I sent him out of the class and he was cursing at me. I called him to keep quiet and don't disturb other classes nearby. He try to run away from the spot which i called him to stand. I warned him not to run away if he does i will report to the discipline unit. I did write down what happen between me and the boy in the absentee file just to back me up. The next lesson, the boy was well behave and listen to what i taught for the whole lesson and did his work. From this incident, was the boy trying to 'test' me? because i am a new teacher. I did ask his previous science teacher. He also did the same things to them just that she ignore him or sometimes handle him herself. What happen to our kids nowadays? ...... They are not well behaved, less motivated and no respect to their teachers which compared to my schooling year.  I greet my teacher 'good morning' or perhaps a smile to them if i past by them...........