Saying no and disagreeing

I used to believe that I am capable of saying no when I mean no or when disagree with what the other person is saying. I firmly believe that I will not be bossed or pushed around because I'm strong enough to voice what's on my mind.

Or so I thought.

Lately, I find myself giving in and keeping my mouth shut even though I don't want to and think what the other person is saying is completely rubbish.

I smile sweetly and accept a new assignment even though I'm already on 3 other jobs and I don't think I'll have time to do it.
I say yes when people asked me to do mundane and rubbish jobs even though I think they should ask the new graduates to do it instead of me.
I give in to arguments even though I believe that I'm right and they are wrong.
I shut up even though I am irritated with what the other person did.
I go along with other people's plans even though it disrupt my own plans.
I stop saying no to things that I dislike.
I do favours for people that I don't even like and probably will never appreciate it.
I sometimes let people get away even though I know clearly that they are taking advantage of me or people that I care about.
I stop voicing opinions which I know people will disagree with.

Have I become more mellow throughout the years? Or am I just too tired of arguing? Have I stopped being the strong-willed girl that I thought I was? Am I no longer that outspoken and loud person that I used to be? Does this make me easier to get along with or am I losing my identity?

Have I changed for the better or the worse?