I struggle with both but there are ways to alleviate growing pains, avoid general suffering and frustration, and to enjoy the hair you have while it is growing. These tips have kept me more or less sane over the years (that's right, years) that I've been growing out my pixie cut (2-3 years).
1. Enjoy the hair you have: hair toys (!!!) buy them, use them, make them yourself, borrow them, whatever you want do. Hair toys are a great way to enjoy the hair you have and make it prettier (dress it up).
2. Enjoy the hair you have: updos (!!!). Google tutorials, find youtube channels, websites with tutorials, buy a book on it, whatever you want. The more your hair grows the more you can do with it, and speaking from experience there isn't a lot you can do in this department with short hair (above chin), but for shorties there is always #1. Examples of fun updos (that also keep your hair protected from tangling and other mechanical damage, thus helping you grow hair faster by not loosing length to breakage and removing split ends - since you will have less): braids, buns, half-ups (for shorter lengths), double buns, double braids, tucks, twists and anything else you can think of. Careful: do not make your updos too tight (this can cause bald spots and permanent hair loss-locally, more info here: webmd-hair loss), and do not use toys that break your hair (hair ties with metal, claw clips that snag your hair or have rough plastic edges, etc).
3. Enjoy the hair you have: hair products. Find the perfect conditioner, shampoo, oil, styling product, hair comb, whatever you use for your hair. I recommend avoiding harsh chemicals and going as natural as possible. This can be fun because there are MANY products that are very cheap and will do wonders for your hair: V05 conditioners, coconut oil, castor oil (for the scalp), etc.
4. Enjoy the hair you have: methods. There are many methods to go through, for example: detangling with a wide tooth comb, finger combing, conditioner only washes, water only washes, baking soda and vinegar rinse washes, shampoo bar washes, preening, boar bristle brush (BBB are to be used on already detangled hair to move natural oils down the length, THIS is the brush that you're suppose to use for 100 strokes a day), scalp exfoliating, scalp scrtiching, protein masks, deep moisture treatments etc, etc, ad nauseum. You can find a lot of hair information on TheLongHairCommunityForum, especially in the hair care section of articles .
5. This is a tough one because some people profit from it, some do not, I personally love it so here it is: taking photos of the back of your head with your hair down. Why? So you can see that your hair has actually grown. You can do this every month, 2 months, 3 months, however often you want, but it will show you how much progress you've made. This is important because hair grows very slowly and sometimes it can seem to never grow at all, when it actually is growing. Photos won't lie to you and you will see your progress which can motivate you to keep going and also give you a bit of a smile. :)
6. Try to follow steps 1-6 while concentrating on small goals, not big ones. For me growing from a pixie cut to having shoulder length hair that is all one length took 2.5 years. If I spent all that time thinking about how far my ultimate goal of classic length (under the butt) is then I would have given up a long time ago. I usually focus on small goals, example: my first goal was to feel my hair on my neck, second was to be able to make a ponytail stub, third was to be able to do anything other than a ponytail, fourth is to be able to make a decent French braid or any bun, etc.
My last thought is that if you enjoy your current hair, see progress and focus on small goals, then the growing pains and general frustration/suffering will fade away. Always remember that the most important thing about growing long hair is to enjoy the journey. Happy growing! :)