As with a lot of anti-depressants their effect varies from person to person so unfortunately they may work for some people and not for others. My boyfriend took citalopram for a few months before moving onto venlafaxine.
At the time he was really very depressed and his mood was terribly unpredictable yet after a few weeks of taking them it seemed to even out a little. He didn't seem particularly happy as such, he was certainly less depressed but very much apathetic (which probably relates to the 'numbing' effect people are mentioning). He said that his mood swings were a lot less erratic but at the same time he just felt 'a bit out of it'.
As others have mentioned the sweating is a major side effect, as another friend of mine has complained previously, particularly during the night. Also the dry mouth, lack or gain of appetite, nausea, fatigue, decreased libido and if he ever missed one he used to get quite shakey.
Oh, and never drink alcohol when taking them (and most anti depressants I guess), I have witnesed some disasterous effects from pills and only a few drinks.