I have been putting a lot of thought into how and with whom we spend our time. One issue that stands out for me is the choice of whether to spend spare time alone or with other people. Individuals often define themselves in terms of whether they are/are not 'people persons'. It seems that there is an expectation that you will categorise yourself in one of these ways. So, first off I want to make the point that you don't have to do this!!! From my anecdotal experience, being perceived as living on the extreme of one of these planets means you are potentially going to be given a hard time. Too social, and you might be labeled 'needy'. Too solitary and you might be judged to be a loner. I think this is pretty unfortunate because neither is objectively good or bad, but society seems to jump in and place value judgements on both such orientations.
Whether socialising or 'me time' is good or bad probably depends on a more complex set of considerations. These might include (but not limited to) evaluating the circumstances you're in, how these situations make you feel, and to what extent you can switch between solitude/social time. Selecting how much social contact you have should be something you can do flexibly. This involves having some awareness of when it might be best to spend time with others vs alone. Operating at the extremes might well lead to problems. Cause for concern may also arise if your preference for social/alone time leads to distress or negative implications for yourself (and/or those around you). For example, there's nothing wrong spending a weekend with your own company (unless you beach yourself on the couch in your underwear with pizza crumbs on your belly while watching re-runs of an Australian soap opera). But if you have done that every weekened for two years and feeling quite depressed, this is likely to be a counterproductive strategy.
As I've hinted above, one of the challenges in managing your preferences for social vs alone time are the value judgements that society can places on both these states (particularly at the extreme end). As someone who prefers time to her/himself, you might be labeled as 'unsociable', 'grumpy', or 'odd' in extreme circumstances (in addition to the 'loner' tag). I think this can be a particularly difficult situation to cope with because humans are seen as inherently social with society geared towards people being together. For example, as romantic couples, teamworking on the job, and being pro social media. Being single can be a real challenge as adults age because it goes against the norm in most Western societies. "Have you got a man yet!?", "Still don't have a girlfriend? What's wrong with you; are you gay or something?" Conversely, if people thing you're too social, you might be described as 'needy', 'emotionally dependent', or 'scared to be alone'.
I am particularly interested in people who like to spend a reasonable amount of time on their own. It is really important to give yourself a break (if you need to!) and remind yourself that it's ok to be 'private'. This can be hard if you feel a lot of pressure in your life to be a certain person. But, humans are incredibly varied. Because I am a psychologist though, I do have to ram home the message about raising the alarm when faced with negative consequences. Many mental health problems affect levels of social contact. Depression is a good example where social isolation can occur. Obviously, this situation is not ok because the social isolation is more the result of being depressed, rather than a free and healthy choice. The other common mental health issue of relevance here is anxiety (particularly social anxiety and panic).
If you wish, you could think about explaining to others your preference for spending time alone. You may have done this already. To maximise your chance of success with this strategy, you could potentially explain the benefits for you. This could help someone understand why you have this preference. Also, it pays to be on the look out for situations where other people take your preference personally. For example, someone may think you don't want to spend time with them. It can be helpful to talk about this but, at the same time, you should not feel that you have to give long-winded explanations if you don't want to.
The only person who is guaranteed to be with you from the first until your last day is yourself. So, I think it's a great life skill to be happy in your own company.
Oh, and I forgot to use the word 'introvert' until now. If you feel this is an unfair title to slap on someone, you might be interested in Susan Cain's book 'Quiet: The power of introverts in a world that can't stop talking'.