I've seen nimble-fingered people picking at the roll of tape so they can complete their packaging job. It's that much more of a challenge for those of us with less-than-agile fingers.
Here's a little trick I picked up from who knows where.
Once you've finished with the tape, place a paperclip so that half of it is underneath the sticky part. The next time you go to use it, just grab the paperclip and start taping! It's such a simple solution, and one that is so much easier than wielding those specially designed roller tape dispensers that just seem to make a mess.