Unless you have personally gone through a professional recording session, you can really have no idea what it is like. Technology has come a long way since the time of the early reel to reel tape recorders with one or two microphones in a room and any editing done with physical splicing together of actual tape. Nowadays, many different microphones will be used to capture the sound of a choir or orchestra or soloist -- some just for amplification and others just for recording. With digital technology, the edits can be made while the sound engineer looks at a computer screen. He can monitor by micro seconds to synchronize the sound waves and punch in precisely note by note, pitch by pitch, word by word to create a perfect performance from pieces of many "takes." They even have "auto-tuning" pitch correction technology available now. Whether they realize it or not, the public has become conditioned to "studio engineered" recordings -- so much so that when they go see an artist perform "live" and "in person" they are seriously disappointed when the artist doesn't sound like they did on the recording.
Personally, I would rather listen to a solid, heart-felt performance than a perfectly engineered, but rather sterile, performance. I was watching a series of movie clips of Judy Garland the other day. The host of the program told of how Judy Garland was known for doing her sections of the enormously complicated production numbers in one "take." She put so much heart and soul into the performance that though the pitch or quavering of the voice might not have been completely perfect, the overall effect was brilliant. Audiences loved her for the moments when her performance tugged at their heart-strings or brought tears to their eyes. No amount of editing can put heart and soul into a performance. Only the performer can do that.
Now, I am not saying that I enjoy sloppy diction or lazy pitch. But I am saying that a performance devoid of spirit and soul is no performance at all. Whether singer or instrumentalist or chorus or composer, the song's "gotta come from the heart."