Sex is like air. It's no big deal unless you're not getting any.
Okay, enough of the one liners. For me, there are several facets to tickling. One is the sexual aspect. Being tickled by a woman during or before sex is most hot. A well timed tickle during sex can send one over the edge into the abyss of orgasm.
Then there is the fun aspect. It lightens the mood, and can break an otherwise tense moment. Tickle fights are fun to win but more fun to lose, at least for me. Tickle fights are especially fun in a swimming pool. It's harder to run away and there is more skin exposed. Gotta watch for choking, though.
There's the torture aspect. Tickling can very quickly pass through the door between fun and abusive torment. Everybody that has ever confessed to me a hatred of being tickled was because at some point in their lives they were abused with it.
Finally, there's the affection aspect of tickling. Often between family members or relatives, tickling is demonstrated as an act of love and affection. Almost everybody has that one aunt or cousin who is a notorious tickler.
For many, there is only one aspect. For example, many folks in the on-line tickling community view tickling strictly as a sexual fetish, and are appalled at the idea of children involved in any tickling whatsoever, completely forgetting that most of us derived this very fetish due to childhood incidents.
Conversely, those outside the community who only subscribe to the playful or affectionate aspects of tickling are equally appalled that anybody could derive sexual stimulus from it.
Finally, those that view it strictly as torture brand any tickling whatsoever as abusive, and categorize it right alongside the backhand.
It's all in the point of view I guess.