Sometimes it’s natural to not complete a goal due to things like holidays. Hover over a goal and you’ll get a little clock icon that you can click to pass on achieving a goal for that day.

When you skip a goal, it causes that day to be excluded from streak calculations. So if you have a streak of, say, 3 then skip a day, it should remain at 3. Then if you completed that goal the next time it came around (the next day, say), your stream would then be 4, as if that day never happened. So in particular it won’t cause streaks to reset.

You can also set past goals in the streaks section so if you missed any days before this feature was introduced you didn’t intend to carry out your goals on, you can amend them and your streaks will reflect what they ought to.