Thanks, that would be great
What is this Slovak betrayal you're talking about? What did they do? I've just taken a real interest in Czechoslovakian history.
Many Czechs simply feel that Slovaks betrayed them. It is not strong feeling that would have consequences in real life, but it is present in their minds.
Czech lands (Bohemia and Moravia + that bit of Silesia we kept after the glorious Empress Maria Theresa lost her war against Prussia - women

) have always been the most developed part of Austria-Hungary. Actually, about 4/5 of the Austrian industrial production were located in the Czech lands (
important un-patriotic note: besides 7 million Czechs, there were also 3 million Germans living in what is now the Czech Republic).
After WW1 and the birth of Czechoslovakia, Slovakia remained one of the poorest country in Central Europe. It was undeveloped, it had not an evolved national identity and it was half-way "hungarized". Czechs invested
HUGE money into this region, they have built roads, railroads, factories, almost the entire infrastructure, schools, hospital etc. Simply put, they tried to change it from a poor agrarian country to a modern industrialized country.
This process was halted by Munich agreement (Czech often say "Munich dictate" or "Munich betrayal") and subsequent Nazi occupation, during which Slovaks declared their "independent" state. Moreover, they expelled tens of thousands of Czechs (teachers, doctors, lawyers, officers etc.).
After the war, they came back and acted like nothing happened. Czechs were stupid enough to buy that and they erased that from history, in other terms, gave them another chance (if Slovakia remained independent, it would be treated as defeated German ally).
During the communist rule, which was arguably imposed on Slovakia by Czechs, Slovakia received one half of the federal budget allocation, although it made up for only 1/3 of the Czechoslovak population. Money were still transferred from richer Czech lands to poorer Slovakia.
After the communist regime fell, Slovaks expected this to continue, Czechs disagreed, so we split up, but many Czechs thought Slovaks acted dishonestly, like they used them when they needed them and when the money stopped flowing in, they separated from them.
But I think that after 14 years of independence, these attitudes are becoming less important.