I always make people feel awkward, why?

Stop focusing on yourself. Instead focus on the other person. When someone comes to your house to perform a service, they are not there to socialize with you, they are there to get on with their job.

Many of us face this problem in a foreign country because we tend to speak the language we’re used to, and we do not want to overcome the awkward feeling of speaking a foreign language. The main goal for you is that others understand you and you being able to understand other speakers. Don’t bother what others think, as time goes by, you’ll improve. Keep practicing!

But your English seems to be on native speaker level.

Are you sure that you make people feel awkward or do social interactions with other people make you feel that way?

I think @marinelife hit the nail on the head. Stop focusing on the fact that YOU feel awkward and focus on your guest. For service people, make sure he or she has everything he needs to do his job and then do what you can do to make his job easier – turn down the tv, put the dog in the backyard, whatever. He will be focused on doing his job, not wondering why you’re not entertaining him with witty conversation. Most likely he will not be thinking about you at all – as shocking as that may sound!!!

I think @Simone_De_Beauvoir‘s answer nailed it. I went through a phase when I would worry about what other people were thinking about me, but it was pointed out that most people are usually so absorbed with their own lives that they really don’t spend as much time analyzing us as we fear they do. Knowing and internalizing that fact really made the anexiety fade. It helped me be myself and be less anxious, and created a virtuous cycle.

Just relax and be yourself and don’t be overly concerned about the language. You’re trying too hard at times I think. Just go easy. You have a lot to offer.

The pragmatics of interaction in American English and Greek are different.

I don’t have any resources to hand, but there’s a possibility that even though (as attested above) your English is very good, perhaps there is a mismatch in, for example, the greeting scripts in the respective language cultures that means you are applying inappropriate physical and linguistic actions.

The Japanese, for instance, would shit a brick if a stranger kissed them in the way the French kiss people they meet for the first time.

Might you be doing something similar?

Like @the100thmonkey said. A lot of it is cultural. I’m from the US and felt the same way when I lived abroad. It’s something to be mindful of but I wouldn’t be too hard on yourself about it. It’s usually perfectly normal to feel that way.