Correct. It is not like Lent in that Lent is totally penitential in nature. No room for joyful expectation in Lent.
Advent however has elements of both penitance and joy. The following from New Advent Encyclopedia explains it pretty well.
Notwithstanding all these modifications, however, Advent still preserved most of the characteristics of a penitential seasons which made it a kind of counterpart to Lent, the middle (or third) Sunday corresponding with Laetare or Mid-Lent Sunday. On it, as on Laetare Sunday, the organ and flowers, forbidden during the rest of the season, were, permitted to be used; rose-coloured vestments were allowed instead of purple (or black, as formerly); the decon and subdeacon reassumed the dalmatic and tunicle at the chief Mass, and cardinals wore rose-colour instead of purple. All these distinguishing marks have continued in use, and are the present discipline of the Latin Church. Gaudete Sunday, therefore, makes a breaker like Laetare Sunday, about midway through a season which is otherwise of a penitential character, and signifies the nearness of the Lord’s coming. Of the “stations” kept in Rome the four Sundays of Advent, that at the Vatican basilica is assigned to Gaudete, as being the most important and imposing of the four. In both Office and Mass throughout Advent continual reference is made to our Lord’s second coming, and this is emphasized on the third Sunday by the additional signs of gladness permitted on that day. Gaudete Sunday is further marked by a new Invitatory, the Church no longer inviting the faithful to adore merely “The Lord who is to come”, but calling upon them to worship and hail with joy “The Lord who is now nigh and close at hand”.
Advent is indeed a unique season.
Sad to say in recent years many have stopped looking at Advent as being penitential at all. That is one of the reasons for the proliferation of blue vestments. They symbolize joy and royalty.