Several annoyances in the Rectangular Pattern dialog:
1) The Rectangular Pattern tool has a little control like this:
If you have not yet selected Objects and Directions, the numbers that you enter appear in the corresponding places in the dialog box. But as soon as you select Objects and Directions, this little control disappears and the dialog box numbers revert to the defaults (Distance 0 and Quantity 3). So I haven't discovered what good this control is. It seems like just a distraction.
Also the control tends to jump around to different screen positions when you enter numbers from the keyboard or select from the dropdown. That's annoying. It is not quite so "jumpy" when you scroll the quantity with the up/down arrows, but I have seen it jump once or twice in that case too. But of course since the control appears to be useless, there is no point in entering numbers in it at all.
2) The Quantity/Distance values always start out at 3/0.00. It would be nice if the control remembered the last-used values, especially in light of the fact that you often have to retry the pattern command to make it work right (due to difficulty selecting the right object set, and having to try different Compute Option values).
3) The user should not have to deal with Compute Option. It has nothing to do with the user's mental model of the design. All of the other controls in the pattern dialog correlate to the pattern that the user is trying to achieve, but Compute Option is just "try it until it magically works" (or not). The program should automatically choose the computation based on what is in the design, or at least automatically try options from most-efficient to least-efficient until success is achieved. Making the user do that manually is very poor user experience.