That part is actually one of your daily/general goals to fulfil in Lab Rats 2.
There are various ways to solve this with the help of the provided mechanics.
You can either
- use the personal interactions like small talk etc to raise happiness daily/regularly
- create serums and buy policies that allow you to 'force-feed' your employees daily with them to keep certain stats at a certain level
- hire and fire constantly thus never ending up in a quitting situation
The management of your employees is the core element to gain income and drugs to do everything else to/with others. Small talk can reveal the likes and dislikes of a person as can certain business policies. Those cost money to buy and come in various stages thus revealing more of the initially hidden likes and dislikes at hiring stage.
Many dislikes are either connected to certain clothing, colours, days or activities. You can have a person employed with faboulous stats in HR for example that really really hates working in HR though. Revealing those likes and dislikes early on is usually your first step after hiring a person when you cant afford any business policies yet.