In general, not that amazing; the Spanish economy dragged a lot behind the rest of Europe in nearly every respect, including working conditions and productivity.

The Second Republic did offer a lot in terms of social programmes and improved the lot of particularly agrarian workers, who were stuck working as sharecroppers under a relative handful of Spanish landowners before the Republican land reform efforts of 1932. But even these lagged behind expectations and ambitions and the 1932 reform was still not complete by the time the war started.

For urban workers, it was a running battle between the two major unions - socialist UGT and anarchist CNT - against the factory owners. Most workers were required to work piecework on fairly low wages, something that was only abolished (briefly) in Barcelona in 1936 by the CNT. Women could work, but often had to do it from their own homes rather than alongside men in the factories - something the Mujeres Libres sought to change (women's empowerment more broadly was woefully absent from the labour movements at the time as well). Due to the general weakness of the Spanish economy (from overreliance on the colonies that were then lost, then failing to modernise during the WW1 trade boom), Spanish bourgeois lacked the flexibility of their French counterparts in offering concessions to keep the working population happy. Instead, all they could really do was physically break up fights, which contributed to the polarisation and popularisation of far left politics in the era right before the civil war.

Despite all that, Barcelona had a bit of a cultural renaissance in this period. Artists like Picasso were active in the city, and there were preparations underway in 1936 to hold the People's Games, an antifascist alternative to the Berlin olympics of that year. Republican policy also allowed a stronger degree of autonomy for regions than under the monarchy. Catalonia was given autonomous status and from that, Catalan language arts and literature appeared on the streets. In Barcelona the art scene was also considered a part of a resistance against reactionary forces; the city had been integral in its opposition to the monarchy, and was a major CNT power base, something reflected in the uprising itself.

This is combined with several uprisings through the second Republic's life, all of which suppressed quite brutally by the military (including, in the Asturias strike of 1934, Franco in command). The bienio negro or 'black biannum' period began with the 1933 elections until the 1936 Popular Front victory (then war), which saw a right wing coalition of Catholic traditionalists and legalist fascists come into power under the CEDA. The CEDA proceeded to halt and reverse a lot of the early Republican reforms, including the land reform of 1932, bringing a distinctly pro-employer policy back in charge, with heavy handed tactics adopted and approved against striking workers. The leadup to war was full of tit for tat assassinations, and the Popular Front victory in 1936 swung it the other way.

By the time the coup came along, ordinary people were quite polarised, mostly along class lines, but also in some cases regional. Many lower classes felt loyalty to the Popular Front government for what it was doing for labour and land reforms, and working class districts in cities that otherwise declared for the rebellion suffered for it.

Most of Spain's soldiers though were conscripts, not volunteer soldiers, and sometimes had no strong feelings either way, depending on the decisions of the officers to either declare for the uprising or not. This doesn't mean of course that conscripts didn't rebel either; there are numerous accounts of the Madrid uprising, where the barracks flag repeatedly changed from the Republican to the rebel one, hinting at some in fighting during the loyalist attempts to suppress the barracks. During the war, there was also a fairly steady stream of conscripts defecting from one side to the other (usually to the Republicans) after being stuck in the wrong place at the wrong time.

In Barcelona, the CNT managed to mobilise several thousand militiamen to confront the uprising in the local barracks. At the outset of the war, they claimed some 30,000 armed supporters, compared to only 5,000 government aligned Guardia de asaltos and other paramilitaries. At their peak in 1936 they also claimed well over a million members, as did the rival UGT, demonstrating again how polarised Spanish politics had become.

For people who didn't want to choose a side, they were still subject to being conscripted by both sides to fight in the war to come. Franco took extensive use of those conscripts that were captured too. After taking a surrender, Franco would eliminate the political PoWs - those with party or union membership, officers and other open sympathies - then recycle the apathetic conscripts left into his own units.

Local nationalist commanders also preferred the local citizenry to be quiet as well. The infamous Queipo de Llano in control of Sevilla instituted a rule of fear, often going on the radio to boast about atrocities himself. The working class district of the city was bombed and stormed by Franco's Army of Africa. Victims of fighting and executions were intentionally left to rot on the side of the streets for some time as an example for anyone trying to cross him. At the same time, this was coordinated with bread shipments from the countryside to placate the population and keep them satisfied to some degree.

But yeah, life in Spain before the war wasn't amazing - it was increasingly politically polarised and the economy dreadful - and during the war, your best bet would've been to be outwardly impartial to avoid politically motivated execution - there was little chance of avoiding conscription.

(This wasn't very well structured so apologies for it jumping around a fair bit)

Sources:

Kaplan, Temma. Red City, Blue Period: Social Movements in Picasso's Barcelona

Seidman, Michael. Workers Against Work: Labor in Paris and Barcelona During the Popular Fronts

Seidman, Michael. The Victorious Counterrevolution

Preston, Paul. The Spanish Civil War: Reaction, Revolution and Revenge

Acklesburg, Martha. Free Women of Spain