Irrational? Yes, that can be argued. There's more going on though. If soda/snacks are free (and always in stock), there is less mental effort involved for th

Irrational? Yes, that can be argued. There's more going on though. If soda/snacks are free (and always in stock), there is less mental effort involved for the employees. They feel reassured that the snacks are always there when they want them. They don't have to make decisions about whether or not to buy them... actually this is a whole 'nother discussion about micro-transactions, which haven't worked well for the Web. If you give your employees a raise, that disappears into the general fund, and is no longer a separate benefit.