"We become what we think about." 

Earl Nightingale

This means that you have to set your mind to what you want to become and you will soon achieve it. If you think about a goal you will have what you want pretty soon. If you think about something negative, you will become something negative. If you think about something positive, you will become something positive and you will achieve your goals. If you think about bad things and bad things you want to become you will feel bad because you will be tempted to do the bad thing and you will do the bad thing.