One of the differences I find between Czech and English in the lexical sphere is that of the greater or lesser degree of specificity used in referring to certain objects, i.e. the use of hyponyms and hyperonyms.
Consider, in your typical French thriller, when a robber enters a bank, bystanders shout, „Attention, il a un revolver“. Now it would stand out a mile if you translated with the same degree of specificity. Of course, English has a word for revolver, but the more general word „gun“ would be more appropriate here. In Czech, we would be even less specific and shout „Pozor, ma zbran“, or „je ozbrojen“.
Likewise, if I need something to write with, in Czech my first reaction would be „mas propisku?“. English can certainly give an exact rendering – „ball-point pen“ or „biro“, but I would suggest that in most cases we would use the more general category of „pen“. Other examples that come to mind are „automat“, used for any device from a cash dispenser to a fruit machine, perhaps „prasek“ where Anglophones would perhaps often use the brand-name of the medication (maybe this goes for a lot of other consumer goods too), „curtains“, where a Czech would differentiate „zavesy“ and „zaclony“, „sign“ which covers everything from „znamka“, „znak“ and „znameni“ to „stopa“ and „odznak“, and then there is the classic case of mushrooms and toadstools. Any Czech would take one look at your average indeterminate fungoid growth and tell you exactly what variety of boletus it is.