Viero, The word "attitude" can be used generally to describe your mental state or feeling. Your attitude is more important than your successes and failures. With a good attitude you can overcome all your mistakes and weaknesses. I don't like your attitude! Please show some respect for your teacher. "Attitude" can also refer to something specific, usually hostility or self-confidence. Only a woman with an attitude can wear that dress!..........She is self-confident maybe even over-confident. After they received three warnings from the referees, it became obvious that the entire football team had an attitude.....The team is unfriendly even hostile.

It means the way you are thinking (your mentality, your outlook, your perception) is disagreeable. If someone says that to you, yes you have a problem. In your example, "attitude" has a negative implication. However, in most other cases "attitude" is neutral. To clarify which kind of attitude, you need an adjective: good attitude, bad attitude, devil-may-care attitude, etc. "The attitude of many people towards a change in lifestyle is..." simply talks about how people will approach, think of or react to a situation. This is a neutral example.

I just want to add that the utterance expresses not only disappointment but also dislike. Your behaviour is so confident (and maybe aggressive) that shows you do not care about other people's opinions and that you want to do things in an individual way. It may also express disapproval. I disapprove of the way you behave towards something or towards a person. Therefore, the word 'attitude' (whether it is a positive or negative attitude) means the way you think and feel about somebody or something.

it can also be said this way: "I don't like the way you behave." now, if someone says this to you, he/she might be annoyed to what you are showing them (action, gesture, speech, etc). to me, "I don't like your attitude" is rather a blunt statement which could be more degrading as compared to "I don't like the way you behave." :)

It means he doesn't like the way you assume that you are better than other people. If that is what he said then you have a problem.