Eventually, we will be able to stay happy all the time, even in the most difficult circumstances.
The purpose of meditation is to make our mind calm and peaceful. If our mind is peaceful, we will be free from worries and mental discomfort, and so we will experience true happiness; but if our mind is not peaceful, we will find it very difficult to be happy, even if we are living in the very best conditions. If we train in meditation, our mind will gradually become more and more peaceful, and we will experience a purer and purer form of happiness. Eventually, we will be able to stay happy all the time, even in the most difficult circumstances.