Bring the positivity. If you bring positivity and an open, happy and good energy into a conversation for example then that tends to spread and the two of you or more will have happier lunch break, evening down at the pub or coffee date in the crisp autumn sunshine.
Smile. Even if you’re only spending 30 seconds on talking to the cashier in the supermarket checkout line.
Give a hug. It can disrupt negative thoughts and change someone’s mood surprisingly quickly. Use when appropriate though.
Get their favorite takeout food. If you want a quicker option than cooking a meal when they are having a crummy day. A variation on this idea is to get just a small piece of their favorite chocolate or other treat.
Share something funny you found online. Play one of your favorite clips from a stand-up show you love if you are out of jokes and good stories at the moment.
Encourage. The world can be a tough and discouraging place at times. So encourage someone who is in a negative situation at the moment. Add your own perhaps more grounded and optimistic perspective on the situation to lessen his or her worries and perhaps exaggerated fears.