One of the teachers I've met last year was Sunita. In the short time that she taught me on counselling, she had became one of my mentors as well.
Both Sunita and Maithilii are always seen happy. On one occasion, when I asked Sunita her secret to being happy / cheerful, she said that she took the time to reflect every day for about 15-20 minutes on the day.
Reflecting on the day, what has been achieved that day, and what can be achieved the next day, is one of the ways to being happy.
Each day of my life can be made to be a better day than the previous day. The secret to it is reflecting.