Over time, things sure do get weird when it comes Facebook friend requests. [Truth Facts]
Now do one for LinkedIn. That one starts with work relationships, then goes to people that were in the same major (and thus have similar jobs), then family (even though you know very little about what they actually do for a living), then friends because they think just because they know you they should also be connected through a work network, then desperate people that are trying to get a job in a similar field or think you may be able to get them in where you work.
And continuously you'll get random requests which usually turn out to be recruiters who can't just send you a job posting but rather feel they have to actually add you to their network.