Some people surround themselves with things to make up for what they believe to be lacking.
An adult surrounded with too many plush toys may be feeling unlikeable down inside, and may be trying to make up for it.
A teenager with scary apparel may actually be afraid of getting hurt, and may be hoping to discourage malicious people. Unfortunately, this approach may discourage harmless people too.
Someone constantly praising himself/herself may be feeling worthless down inside, and may be desperately trying to show the world that he/she actually has qualities to be loved.
A hobby musician with extremely expensive gear may be feeling like he/she lacks musical skills, and may be trying to cover this insecurity with gear; assuming to be a musician as good as his/her gear.
You get the idea.
Now that you know this point of view; use it to fuel your compassion, not judgement.