Remember whence you came. Do not underestimate the power of nostalgia. Swapping stories with friends can help us view ourself in a more positive light.
Mulling over past failures can be tempting, you may even feel like you are gaining insights. This behavior may over time lead to feelings of helplessness. This is something that I struggle with frequently. Studies show that ruminators are more likely to be depressed, due to a downward spiral of emotions.
Giving away money or giving of self studies show increased happiness. I love to buy gifts for other people, not that I don't buy plenty for myself. It is fun to see friends' pleasure.
Eat a snack around 2:00 p.m. Serotonin levels can take a nosedive around that time. It is so hard not to snack at night! Nothing tastes better than eating popcorn around 9:00!
Get a move on! For some people, exercising at high intensity 3x a week for just 30 minutes can be very helpful. I have been in a wheelchair for the last 2 years, so I keep having to develop different type exercise strategies. It is an uphill battle....
Limit your options. Try to whittle options down to a few choices, then pick one and move on. Sometimes even picking out fingernail polish color can be frustrating.
Find something that occupies 100% of your time while you are engaged in it. I love arts and crafts, so I have started new hobbies in that regard that I enjoy very much! That keeps me from being a shopaholic as much!
Like my sweet Mother always said, "make your bed." I can be very lazy about making my bed, but it really does feel good when it is made.
Take care of yourself.
I agree with you that sharing fun memories with a friend is good for the soul! It's the best! It is also wonderful seeing friends smile when I give them a little surprise gift. Brings a smile to my face, too!