Can a person be dismissed because their attitude has changed, been so said to "snub" some of the management. They are considered an temporary employee and been with the Company for over 3 years

An employee can be terminated for any reason, as long as it's not discriminatory and you are paid the appropriate severance. If you have recently been terminated, I would still strongly suggest that you speak to a lawyer to ensure that you have been provided with the appropriate termination package.