I enjoy meeting new people - Every time I meet new people, I enjoy it. I am enjoying the party - I am at a party now and I am enjoying it. The difference is the same difference which always exists between present simple and present continuous 🙂

The first is a declarative statement that you use to describe an action or thin you enjoy. “I enjoy running”. The second is the gerund verb form and implies you are current doing [verb] and enjoying it. “I’m enjoying running (right now)”