steepholm

I kind of thought it was polite to thank people, that it was standard practise. I usually thank beta readers, particularly if they are kids; if someone has slogged through a draft mss as a favour, a public word of thanks seems appropriate. If I cook dinner and someone brings wine or a pudding or tells me how to rescue something I've messed up, I'll acknowledge their contribution to the meal and I don't see that as hubristic. I see the acknowledgements as a way of recognising help - getting a work of fiction in front of an end reader is not a one woman job.
OTOH I rarely read other people's as I expect them to be as dull as my own so maybe I would be more irritated by them if I did.