Tell yourself I am the happiest person anybody knows.
I am not talking about denying when things are going wrong. Or if you have issues in your life.
But it is developing a core belief about yourself.
You are a happy person, the happiest person anybody knows, and you may just be going through a rough spot.
That belief becomes a core belief, part of your identify, and self-fulfilling.
What do you do with issues you have?
There are various types of issues. Take care of your own garden first.
Physical - get sleep. exercise everyday (get a sweat). eat healthy food (lots of dark leafy greens, fruits, meat, i also like rice).
Mental - there are multiple aspects to this. there is the mind. so sleep again. have optimistic beliefs. let go of anger or process it through art and therapy.
there is also the spirit. go into nature. sit in a park in the sun, have your bare feet on the grass. you can do whatever you were going to do inside anyway (eat, call friends, text people, read a book, browse the web, write) but doing it outside feels so much better. express yourself through art. play piano or another instrument. write. meditate through these mediums too.
Social - social is important even for introverts. writing a letter is nice, receiving is very nice. but a text chat is nice. a phone call is nice. but a phone video call really makes a difference. in person is really nice too, meet up for tea and get boba. go on a walk. my friends and i have sometimes gone to the park with a bunch of outdoor gear (basketball, skateboard, frisbee) and just mess around. tell stories. laugh.
Do things yourself. When in doubt, err on doing things yourself, err on doing things that are real, err on doing things that are active.
Watching TV is passive, acting out a play is more active, watching an action show is passive, boxing muay thai wrestling are active and more real, video games are active compared to watching TV they are passive compared to going outside they are not real compared to meeting up in person. An e hug is not the same as a hug.
Getting your computer repaired is good, repairng it yourself may be better and faster and cheaper, or it may not be. Develop the skills and you pretty much do not have to go out for repairs. Same with a bicycle.
There are so many things and cases in life, that there aren't any hard and fast rules. Do stuff and see what works, what feels right, and why. You'll figure it out.