In the valence bond (VB) theory, hybridisation of water (H₂O) is sp³ yet the bond angle is 104.5° rather than 109.5°. This is because:
AH atoms are too small to repel each other properly
BLone pair-lone pair repulsion > lone pair-bond pair > bond pair-bond pair
CThe O-H bond is polar, causing bond angle reduction
Dsp³ hybridisation always gives angles less than 109.5°