Mike is present in the den, watching the game, but the two friends do not notice each other at first.

There were hints over the years that my friends and I should have noticed.

Other friends noticed a change in him, as well.

And his friends noticed that he ate much faster than they did.

My friends and family hardly notice that there's anything different about me.

And one morning he got so restless that even his friends noticed it.

The change was minuscule, something that only a friend would have noticed.

Your family members or friends may notice that you're having trouble understanding what others are saying.

His friend had noticed the odd bit of decoration, too.

The other side of this is that friends notice personality changes, for the better or the worse.