on what level you play. The lower the buy-in's the more luck plays its part. Regularly, players will call big bets with low pockets knowing they are big underdogs, but also knowing that they could hit their set.
This is relying on luck, which is not great in the long run, but a common practice in lower level online games.
MY guess would be that more skill is required in the bigger buy in games - but my experience of low level buy ins - is I'd rather be lucky than skillful.