Why hasn't he responded to my friend request yet?

I sent it 2 days ago today but he hasn't accepted or deleted it. I know he accepted someone elses the night before like right after it was sent. So is it possible he just hadn't seen mine yet or is he ignoring me on on purpose? He talks about Instagram way more than facebook but the fact that he added this other person soon after is making wonder what is up with him. We're all coworkers, even the other person who he accepted. I don't know what to think. Should I wait & see or should I delete it? We are both off today so I won't see him till tomorrow...
Why hasn't he responded to my friend request yet?
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