Oh yeah, I always keep smiling and say "I meant to do that" when I miss step or get out of rhythm.
No need to say anything, just keep going. No need to apologize, and certainly no need to pretend like you're doing something on purpose that you're obviously not.
When I dance with new dancers at parties, my repertoire consists of a waltz box step in the middle of the floor, foxtrot SSQQ basic, american tango basic, or the rumba box, cha cha side basic, and swing basic, all done out of the way of other dancers who might run into us.
Your problem is not that you have a limited repertoire--your problem is that you don't really know well how to do the things you already know. Adding more figures will only add confusion and frustration. Increase your repertoire as you get better at your current figures, but don't just add more figures without adding the knowledge of how to do the ones you already do. You may feel you are progressing slower this way, but take the advice of most everyone who's commented on this thread--QUALITY matters more than QUANTITY!
It seems that many men have their priorities all wrong when they dance socially. Their primary goal when dancing is to try and dance every figure they know how to dance. Because many haven't learned how to really dance the figure and lead it, 90% of their figures (at least) make them and their followers look terrible, and ultimately the men are the ones who end up looking foolish. I think it's linked to ego, the feeling of having something to prove or show off. I used to feel the same way, but then when I became a capable dancer socially, I then lost the need to have to "show off" and so I'm quite content to dance basic figures with newer dancers rather than drag them around the floor trying to get them to do things that even the perfect leader couldn't get them to do.
The primary goal of a good leader socially, IMO, should be to have as enjoyable a dance as possible, while giving the lady clear signals that
SHE can follow, and first and foremost keeping her free from harm such as being stepped on, running her into people or objects, and so on.