Did you take in account that with 3000€ salary, if you work in addition to that the tax increases and all ultimately cause that every additional € you earn will increase your income by 0,5€.

If you'd get 2200€ after taxes from the 3000€ and get another job (or a raise) and get 600€ more, you'd be most likely earning 2500€ after that. Magrinal tax rate in Finland is high. But it's always a bonus.

Luckily salaries are OK too. If someone would pick a side job with 15h/week, they could easily get approx. 10€/h AND if they'd be working in the evenings/weekends, some extra money on that. Would be more than 600€/month (before taxes) and even with taxes deducted, it'd still make a difference in the long run.