So what if God did the same thing? He'll give you eternal salvation but you have to be good and do x,y, and z. How would you feel about that?  Questions would arise, how much would I have to do? How often? For how long?

This is one of the problems when people read this passage, they interpret it to mean you must "work" for the gift. (note: if you have to work for it, it's not a gift) Do people have to "work" for their salvation? Do they have to earn it by being baptized, going to church, being good, etc.. People add work in two ways, either before or after salvation. People will frontload the gospel by adding works to be saved or they will backload it by adding works to prove you were saved. Either way works becomes consequential to receive the gift of eternal  life. 

As can be seen, work, at any level, becomes an impossible standard. In this podcast Charlie expounds on the meaning of Paul's words; rest assured, salvation IS a free gift, no strings attached.