350 is an arbitrary number; the point is to be happy for most of the times but not always.
It is healthy
From a biological point of view, there is no negative emotion...we are gifted with a myriad of emotions so that we may experience its full spectrum that comes with a rich and fulfilling life...in support of our human experience.
Each and every one of our emotions has a role in the biological system that is primarily meant to serve us, not to sabotage us. It only becomes negative when one is not able to manage it and use it constructively.
Perhaps for every emotion that you think is negative, there is a higher intelligence to support the reason for its existence. But human intelligence hasn't caught up with Nature's intelligence.
A healthy and robust psychology can and will experience different emotions other than 'happy' from time to time with no detrimental effects to the subject at all but contribute to the subject experiencing a more sophisticated, meaningful and richer existence.
To help you evolve
From an evolutionary and philosophical point of view, pain is essential for growth because few people can motivate themselves to change without a trigger.
Usually, this trigger comes in the form of an unpleasant experience...something that pisses one off and have one feeling they have had enough and will tolerate it no more.
If everyone is happy every single day, they will all be chilling at the beach even when what they need is some serious reflection and thinking.
Sorry to say but pain is perhaps the most effective change agent.
Hence I found the below excerpt of Supreme Court Chief Justice John Roberts' commencement address at his son's ninth-grade graduation especially brilliant:
"From time to time in the years to come, I hope you will be treated unfairly, so that you will come to know the value of justice. I hope that you will suffer betrayal because that will teach you the importance of loyalty. Sorry to say, but I hope you will be lonely from time to time so that you don't take friends for granted. I wish you bad luck, again, from time to time so that you will be conscious of the role of chance in life and understand that your success is not completely
deserved and that the failure of others is not completely deserved either. And when you lose, as you will from time to time, I hope every now and then, your opponent will gloat over your failure. It is a way for you to understand the importance of sportsmanship. I hope you'll be ignored so you know the importance of listening to others, and I hope you will have just enough pain to learn compassion. Whether I wish these things or not, they're going to happen. And whether you benefit from them or not will depend upon your ability to see the message in your misfortunes."
I too hope that Life will not be too smooth-sailing for you
because what's the point of making it safely to the graveyard?