When I was a kid, my parents thought it was too expensive to heat up enough water for my younger sister and I to have separate baths. She had her bath first, and then I had her used water. Mum and dad did the same - she had first go, and dad had the secondhand water.
I didn't mind too much when we were younger, because I had a later bedtime than my sister, which I felt balanced out the fact that I never got the clean, hot bathwater, and I had to do all the tidying up afterwards - cleaning out the bath, hanging up the towels and the bath mat etc. But when we both became teenagers, and had the same bedtime, I thought it was not fair any more. We only had baths twice a week (another sore point - mum refused to buy me antiperspirant so infrequent baths, and no antiperspirant means I know I honked at school), so I asked my mum if my sister and I could take turns to go first in the bath - and my mum refused!!
Looking back, I wonder whether she didn't want to have to admit it wasn't fair that I never got the clean bathwater, because then she'd have to admit that it wasn't fair that dad never got it either, and she didn't want to give up her clean bathwater. Or it could just have been that she favoured my sister (always has, always will).
For my 18th birthday, I got a £21 clock radio. For her 18th, dsis got a £250 oboe.
My mum carried on doing stockings for us even when we were teenagers - which was nice. But one year, the main present in my stocking was a pair of knitting needles and enough wool to knit my dad a scarf. That's right - my present was actually for someone else! Very unusually for me, I stood up for myself and said I didn't think this was fair (I was afraid of mum, and generally didn't dare talk back to her) - and she said I could have the money if I wanted - but it was SOOO sad because she knew dad would LOVE having a scarf I had knitted for him, and she thought I would WANT to make him happy! Basically she guilt tripped me into saying the present was fine.