"One of the biggest determining factor in how our training goes, is the attitude we bring to it."
How we frame situations in our own mind plays a big role in the attitude we bring to them. If we want to be a positive person then we need to frame things in a positive way.
A great example of this is when people talk about all the sacrifices they make for their running: "I give up sleep, I give up family time, I give up sweets". This can be a negative way to approach training and leave one feeling bitter, burned out, or even resent it, especially if things do not go well in a particular race or training cycle. Instead I suggest we would be much better off by viewing it (framing it in our mind) as making a choice. We choose to go for our runs because the sense of accomplishment (or whatever it means to you) is more important to us than whatever we give up (such as an extra 30 minutes of TV). We are simply choosing to value our running goal more than some other uses of our time. Those other uses may be great and valuable, but whatever running goal we have is more important to us.
This is a decision to focus on the positive, to focus on the positive things we are choosing rather than the negative of what we are giving up. The end result is a greater feeling of empowerment and control and affirmation that we are taking positive steps towards our goals, which leads to a positive attitude. But if we dwell on sacrifices, we are focusing on the negative and what we are giving up, which leads to a more negative frame of mind.
As you go about your day and your training, focus on your choices rather than your sacrifices, and you'll stay happier, more positive and be more effective.