Even when considering total tax wedge, which is not what most people consider "their" tax (note total deductions from your contracted salary is 38% at 120k salary; the total cost to your employer is ~136k because of the employer contributions), only a tiny minority pays that much. E.g. 120k places you in top 2% or thereabout.

The average UK salary is <35k GBP. At that level total deductions are 20%, and your employer pays 10% employer NI.