Succinctly: you can have sensible default reactions so your brain isn't spinning and the reaction is smooth (think cache). You can take advantage of low stakes contexts to train, as opposed to trying things in a professional context where the price may be hefty(think sandbox). Empathy: seeing a situation from the perspectives of all people involved is
extremely useful, effective, and profitable.
Details and rationale:
There are a lot of common situations. These are situations that either have a high probability of happening in a context, or happen frequently. Note I didn't say XOR.
For example, someone complimenting you. A default reaction would be to smile, and say "thank you". Making eye contact with someone: smile and say Hi/Good morning.
This will take the load off of your head. Most people I've seen who describe situations they reacted inappropriately in simply don't have a repertoire or haven't been around the block. Many people get "weird", in their own words, during some of the most banal reactions.
Sandbox: practice on the streets. Buying coffee or groceries. Being tactful and smooth takes practice, and witnessing instances of handling situations. Leveraging everyday situations to learn more about people and expanding your comfort zone. For some people, holding a five minute conversation is daunting. They can practice as they go about their business. The pressure to do that in the workplace can be unbearable, and inappropriate behavior may be a consequence of that. Low pressure situ, low stakes.
The empathy part: the ability to predict how a situation or event will be lived/interpreted/felt by different people is, again, extremely useful. In a professional context for example, running a decision to be made against different world corresponding to people will often lead to a pause and figuring out it ought to be changed because X or Y. In meetings with clients, it allows to have a loop running where you interpret what something means for one member or department of the client organization, and how it'll play with other departments.
Again, this is extremely useful.
Also, as an aside for professional contexts and useful things to do/learn: the moments before, but mostly after a meeting is over where you chat up the people who were there are the most valuable. You rally learn things and information that couldn't/wouldn't be shared because of inhibition or other factors. People will share fears, apprehend, resentment sometimes, enthusiasm with you.