Loneliness is deadly, according to recent press reports. Social isolation is actually harmful to mental and physical health, much like smoking and obesity. Even convicts who suffer from the violence of other convicts dread solitary confinement. We know that this is one of the harshest punishments in existence that is not the infliction of serious physical pain. It is the confinement that makes it harsher, but the solitary aspect of it is also harsh.
So solitude, to be beneficial, must be managed.* And solitude does have benefits. It fosters personal autonomy and freedom, one of the main needs for human beings. So solitude cannot be confining or limiting of freedom (as in the convict example.) Secondly, it must be used intelligently. Do you exercise alone and get enjoyment from being alone, or do you need to exercise in a group? Same for meditation. Maybe you need to be in group meditation center and not all by yourself. Do you need to write in a coffee shop where a friend might drop by unexpectedly, or are you a solitary writer? You won't necessarily have the same example for each of these activities, but answering questions like this will help you. For years I ate meal out simply because eating by myself at home was intolerable to me. Solitude always requires you to be at home with yourself, something that is extremely difficult for me, although I am getting better at it. If I want to play piano in the student union where people are around, I will do that. Rarely will anyone stop by and comment on it, but just the few times it's happened were nice.
Solitude is also beneficial when it allows you to come into contact with nature.
If you aren't at peace with yourself, solitude can be horrible, and you will want to escape always in the company of other people or stupefy your brain somehow. When you do stay home, you might engage in more third tier activities and get more depressed and anxious. But if you practice being alone deliberately and do things alone that you enjoy, you will build a foundation for managing solitude.
Some bad ways of managing solitude: having the tv on at all times, with endless Law & Order re-runs running, doing endless sudoku puzzles on line, or hanging out on Facebook. I've tried these and they are dead ends. The lonely person can become alcoholic in some cases, whether through drinking in bars or at home alone, or both. Wouldn't you like to stop by the bar on the way home from work on a typical night rather than facing an empty house?
*I am calling loneliness something that is experienced negatively, and solitude something that is a potentially beneficial practice with some inherent dangers.