People nowadays are eager to make fun of folks who are obsessed with their mobiles. Memes criticize social media addicts on social media (!) by showing people in public places completely immersed in their devices, instead of talking to each other.
I acknowledge there are extreme cases of social media addiction that make people become anti-social (in the traditional sense of the word). However, I'd like to make the case that in general people are not wrong when they chose to communicate with their friends and loved ones through their hand-held portals as opposed to trying to engage in conversations with people physically around them (especially strangers).
I also admit that on the surface groups of people looking at small screens avoiding in-person contact may look weird. But, one should not judge the situation by just appearances.
It is possible the people physically present are hard to relate to, boring or even annoying. The fact that people happen to sit on the same bus as you, doesn't guarantee you can maintain a meaningful or valuable conversation with them. The people you connect with over the internet will have common values or have shared experiences with you, and are typically interesting or inspiring to you. The conversation you have with these folks are typically more interesting than you would usually have with a stranger.
A rich in-person sensory experience with boring people has much less value to most, than a poor sensory experience over the internet with a curated list of friends who bring you a very personal value. No matter how 'real' your in-person conversation is, a few words or a picture exchanged with your loved one, your best friend, your best colleague, etc. is typically much more fulfilling and worthwhile.
The parallel that comes to mind is this: Compare the experience of what a currently showing high-budget 3D cinematic movie with an average storyline can give you, to the intellectual adventure of a carefully chosen library book with only black letters on white paper can bring.
Even the extreme case of a teenager texting during a family dinner is understandable. The social circle of a teen is much more crucial for social standing than maintaining a good relationship with the family. The teen is about to leave the house and become part of a new social structure. Every text, every alliance is building his or her future in the most literal sense. Texting is not mindless stupidity, it's the manifestation of rational survival instincts.
Does physical presence in communication matter anyway? Our physical bodies aren't our primary way to define a human. People who lose a limb or have artificial organs do not become less of a human. Humanity primarily resides in our thoughts and ideas, not in our bodily tissues.
Does the medium of communication matter then? Let's suppose you are away on a business trip. Does telling your loved one you miss her and love her has less significance because it's done over the phone and not in person? I believe the meaning remains intact regardless whether the words travelled over fiber optic cables or through vibrating air molecules.
Getting to know new people can be cool and refreshing, but there are limits to the number of social connections we can handle. We've evolved to be in touch with only a few dozen people at a time. If you live in a city, the practice of constantly getting to know new people can quickly become overwhelming and disorienting. Social media allows us to recreate our comfortable small circle of friends that we can be regularly in touch with, regardless of the physical location.
I would argue that it's not only not weird to be constantly on your phone. It's the natural thing to do.
Don't let people or brands riding the anti social media hype, bully you into feeling guilty about your social media habits. Let your friends know they are important to you no matter how far they are.