Distractions are all over – some external and some internal. External distractions include TV, phone calls, emails. Internal distractions include things you think about most are the past or future.
People who you are with notice your distractions feeling less important than the things that are distracting you.
When you are distracted you know deep down that you are distracted. Others notice that you are distracted. The outcome is a lack of concentration leading to less than optimum interaction.