Never spend your time thinking what ‘you can't do’ or ‘what if....?’
The best part for me teaching, whether it be in Martial Arts or in I.T. is the expression on a students face of their own recognition of achievement and success. It may be something as small as completing a single unassisted military press up, to faultless completion of a kata / form.
Enjoy your life today, now. Everyone has a potential to accomplish all their goals in life, no matter how abstract. It may take some time but keep going and enjoy the path leading you there. If the destination of your goal is too distant, break it up in to smaller more manageable steps, each one an achievement. Too many people say "I don't have time for...." and this is the excuse they live by. You must take time out for yourself, whether it may mean getting up earlier, going to sleep later or even organising 20 minutes at lunch/dinner time each day.
Sad, or upsetting memories tend to have a deeper root in you subconscious than do good happy memories. Train your mind to re-enact these happy memories in you minds eye this will keep them strong and you will develop a happy optimistic approach to anything life throws at you. As soon as you feel upset or recur a sad memory, stop the flow by occupying you mind with a lighter subject or even better flip the coin and remember something funny or happy. Even if you are in mourning, try and keep out of the spiral of how much you will miss this person and remember the happiness and smiles you shared.
Try and avoid the word "hate" and if you must use a much more forgiving word of "dislike". "You dislike him/her.." Hate is a much darker word conjuring up the wrath of your soul and with it a strong physical feeling of loathing. Let this go or this will eat your life away. Learn to relax. Like it is written "there but for the grace of God go I." Our time on earth is relatively short, make the most of it and yourself....