Spanish companies can't have anybody working (i.e. 'dormant' state), they always need an "administrador" who pays a monthly 300€ self-employment tax. This kills companies in early stages unless they can break even quickly (3600€/yr while not having any income, plus maintentance expenses, is terrible)
Creating a company is bureaucratically difficult, I reckon it was on the bottom area in the latest "easiest countries to create a company on" report.
If you're an exporter, you can go bankrupt because you owe worker taxes to the State... while they owe you return of export VAT. I personally know a case of these. They owed the State about 300k€ while the State owed them 500k€ for more than a year. They couldn't "cancel out" the debt. That is outrageous. They had to file bankrupcy.
And finally, if you're a small company, you have to pay a lot of taxes, while if you're big and can pay big lawyers/accountants, Spain is equivalent to a tax haven (i.e. Ireland). This is true. Spain attracts big companies with a tax maze which allows the rich to evade taxes.
This is really disheartening for Spanish enterpreneurs. We're treated as second-class citizens... in our own country. Our taxes go to finance big, foreign companies. That sucks.
Sorry for all the negativity, I'm currently trying to start a company in Spain and I'm meeting a lot of friends who also have. This is the general sentiment. Spain needs to fix A LOT of things if they want to be enterpreneur-friendly, starting with THEIR OWN enterpreneurs.