Yep, so many "cliff edges" that discourage people working more hours, taking promotions, etc., due to tax hikes or benefit losses.
Like the £50k income threshold where you start to lose child benefit.
Or the £100k threshold where you lose free childcare and the tax free personal allowance.
Or the lower thresholds where you start to lose tax credits or UC, or council tax relief, etc.
ALL these cliff edge thresholds need reviewing so that people are guaranteed to keep most of the extra money they earn, i.e. have a maximum "Loss" of tax reliefs or benefits etc of 50%, so that for every extra pound you earn, at whatever income level, you're guaranteed to keep at least half, 50p of it after taking into account free childcare, child benefit, tax/nic rates, benefit clawbacks etc.
We really should never have allowed a situation where someone can lose 70p or 80p or even all of that extra pound they earn.